Introduction: Stereotactic radiosurgery (SRS) has become a common treatment approach for small-to-medium size vestibular schwannomas.

Objective: To evaluate relationship between time (beam-on and treatment) and risk of hearing decline after stereotactic radiosurgery for vestibular schwannomas in patients with Gardner-Robertson (GR) baseline classes I and II.

Methods: This retrospective longitudinal single-center study included 213 patients with GR I and II treated between June 2010 and December 2019. Risk of passing from GR classes I and II (coded 0) to other classes III, IV, and V (coded 1) and the increase in pure tone average (continuous outcome) were evaluated using a mixed-effect regression model. Biologically effective dose (BED) was further assessed for an alpha/beta ratio of 2.47 (Gy2.47). The mean beam-on time was 36.3 ± 18.1 minutes (range 7.3-101.8). The mean treatment time was 38.8 ± 18.5 (range 9-106). The mean radiation dose rate was 2.8 ± 0.6 (1.7-3.8) Gy/minute. The mean BED received by the tumor was 57.1 ± 4.5 (42.7-66.3) Gy2.47.

Results: Binary outcome analysis revealed sex, dose rate, integral dose, time (beam-on time odds ratio 1.03, P = .03, 95% CI 1.00-1.06; treatment time ( P = .02) and BED ( P = .001) as relevant. The OR of 1.03 for the beam-on time implies a 3% hearing deterioration risk per minute, for 10 additional minutes, OR was 1.38 with a risk of 38% and for 20 minutes was 1.92 with a risk of 92% (P < .001). Fitted multivariable model included the sex, dose rate, and BED. Pure tone average analysis revealed age, integral dose received by tumor, isocenter number, time (beam-on time odds ratio 0.20, P = .001, 95% CI 0.083-0.33) and BED ( P = .005) as relevant.

Conclusion: Our analysis showed that risk of hearing decline was associated with male sex, higher radiation dose rate (cutoff 2.5 Gy/minute), higher integral dose received by the tumor, higher beam-on time ≥20 minutes, and lower BED. A BED Gy2.47 between 55 and 61 was considered as optimal for hearing preservation.

Introduction: Gammaknife radiosurgery (GKRS) is one of the main options for the management of small to medium vestibular schwannomas (VSs) due to its high tumor control rate and low morbidity. When failure occurs, microsurgical removal is generally advised. Yet, surgery is deemed as more challenging, after initial treatment by GKRS. We report our own experience of repeat GKRS using of historical cohort for VSs.

Methods: Were included patients with sporadic VS treated by GKRS in Marseille from July 1992 to December 2017 and who benefited from a second GKRS in our center after initial failure.

Outcomes: 81 patients were included in the study. Median marginal dose was 12 Gy at both GKRS. Follow-up after GKRS 2 was available for 72 patients (9 patients lost to follow-up). Median follow-up after GKRS2 was 56 months. Tumor control GKRS2 was achieved in 92.9% with no patients requiring a further microsurgical resection. Hearing preservation was 61.9% (13/21 patients). No patient experienced persistent facial nerve deficit. New persistent TN was observed in 1.4%, and hemifacial spasm in 1.4%. A ventriculoperitoneal shunt was required in 7%, all after GKRS2. No patients experienced malignant transformation or adverse radiation effect.

Conclusion: We report the largest series of patients managed by repeat GKRS for VS after initial failure. The management of these patients is challenging and requires a multidisciplinary team. GKRS is as safe and effective in case of retreatment compared to a first treatment. This option should be proposed before surgical resection when the clinical condition of the patient and the tumor volume is still compatible. 

Fractionated Radiotherapy for Meningiomas Using the Mask System of Leksell Gamma Knife Icon
Yuta Oi, Gaku Fujiwara, Takuya Kawabe, Manabu Sato
Maizuru Medical Center, Rakusai Shimizu Hospital

Objectives:
The Leksell Gamma Knife Icon has facilitated the implementation of novel immobilization techniques utilizing mask fixation and the option of fractionated treatment.

Methods:
We conducted a retrospective analysis involving 176 patients (209 instances) diagnosed with meningiomas who underwent fractionated radiotherapy using the mask system of Leksell Gamma Knife Icon over the initial 6-year period at Rakusai Shimizu Hospital. A fractionated schedule was applied in cases where tumor volume exceeded 5.0 ml, instances of recurrence, or when the lesion was located in eloquent areas. The reasons for selecting a fractionated schedule (including duplications) were categorized as follows: large volume (122 instances), proximity to eloquent areas (108 instances), and recurrence (45 instances). To enhance precision, we reduced the upper limit of the HDMM system from 1.5mm to 0.5mm near eloquent areas. Of the 112 patients, 112 underwent surgical resection. Tumors were classified according to the WHO classification system, with Grade I representing 116 cases, and Grade II and III combined representing 60 cases. Ninety-two tumors were located in the skull base, while 84 were in non-skull base areas. The median tumor volume was 7.6 mL (IQR: 3.3-13.3). Median marginal doses were 30Gy in ten fractions for Grade I and 37 Gy for Grade II and III.

Results:
The median follow-up period was 21.5 months (range 0.6-69.5). Throughout this period, 10 patients deceased, with seven deaths attributed to neurological causes. Poor local control rates were 3%/4%/11%/15% at 6/12/24/36 months post-treatment for Grade I and 16%/22%/35%/41% for Grade II and III, respectively. Neurological function preservation rates were 98%/96%/92%/92% at 6/12/24/36 months post-treatment for Grade I and 80%/72%/64%/54% for Grade II and III, respectively. Serious complications occurred in only 1%/1%/2%/5% of patients at 6/12/24/36 months post-treatment for Grade I and 3%/3%/7%/7% for Grade II and III, respectively.

Conclusions:
While acknowledging the limitations of these findings due to the relatively short follow-up periods, survival rates, local control rates, and qualitative survival rates among patients unsuitable for stereotactic radiosurgery – particularly those with large, recurrent, or lesions in eloquent sites – were observed within acceptable ranges.

Introduction:

Brain arteriovenous malformations (AVMs) are rare conditions with an annual rupture rate between 2-4%.

Depending on the depth at which they are located, the rupture rate can reach up to 33% in deep lesions

associated with venous drainage. After a rupture there is a 50% probability of suffering neurological

deficits, which are fatal in up to 10% of cases. Radiosurgery with gamma knife is an alternative in those

lesions smallers (<3.5cm), complex or with high surgical risk, achieving obliteration that prevents rupture

and secondary hemorrhage.

Materials and methos:

Retrospective descriptive study of patients with arteriovenous malformations treated with single-dose

radiosurgery in our Gammaknife unit at Virgen de las Nieves University Hospital, Granada, from

November 2022 to October 2023

Results:

A total of 28 patients with a median age of 47 years (18-72) have been treated. 45% were women and

55% men. 3 of them were previously treated with CR and 2 with surgery. The most common clinical

presentation was hemorrhage (46%) and seizures (25%). 86% were <3cm, 11% 3-6cm and 3% > 6cm.

Located in eloquent area 35%. Deep 25%. Median follow-up of 5 months.

Spetzler-martin score: 1 (33%), 2 (33%), 3a (6%), 3b (17%) and 4 (11.1%). Median tumor volume 0.7

(0.04-6.6). Coverage dose 18Gy. Median coverage isodose 58% (47.7-98.3). Median selectivity 0.6

(0.28-0.99). Median Gradient 2.86 (0.8-9.29). Paddick Index median 0.61 (0.14-2.58). Acute toxicity:

perinidal edema G1 21%.

Conclusions:

Radiosurgical treatment with Gammaknife for AVMs is a safe treatment, with a low acute toxicity profile. It

is necessary to obtain greater follow-up to quantify the obliteration rate of the lesions as well as the

probability of bleeding in the latency period between treatment and obliteration.

Introduction

Stereotactic radiosurgery (SRS) is a common option for patients with intracranial meningiomas. Major contraindications to SRS include large tumor volume and critical location (e.g. perioptic). One strategy to expand the treatment envelope of SRS Is to deliver radiation over several fractions. The data on the durability of tumor control and optimal fractionation regimen are limited. Our goal is to clarify these questions through a multi-institution collaborative study.

Methods

We reviewed consecutive patients with meningioma who underwent multi-session radiosurgery at NYU Langone Health (New York, USA; Gamma Knife = 25) and University Health Network (UHN, Toronto, Canada; Gamma Knife = 9, LINAC = 4). Patients were selected for multi-session radiosurgery either due to larger tumor volume and or critical locations. Comparisons of overall survival between cohorts were done using a Cox proportional hazards model.

Results

38 consecutive patients were identified with mean age of 62.9 years and female-to-male ratio of 25:13. 44 tumors in total underwent irradiation spanning all WHO grades. Most commonly, tumors were located in the convexity (n = 14, 32%). 13 patients had previous EBRT while 5 had prior SRS. The mean gross tumor volume was 7.1 (range 0.02 - 64) cm³. The most common fractionation schemes were 20-25 Gy over 5 fractions, followed by 21 Gy over 3 fractions. 

The median follow-up was 26.8 months. The overall median survival was 68.5 (95% CI 36.3 - NA) months, with 3 and 5 year survival at 69.8% and 50.9%. Meningiomas with unknown grade or WHO grade 1 were associated with improved survival (p = 0.026). The median survival of these low grade meningiomas was not reached. The 3 and 5 year local control rates of all tumors were 70.4% and 60.3%. Again, WHO grade was associated with tumor control (p = 0.022). The 3 and 5 year local control rates of low grade meningiomas were both 91.7%. 

13 (34%) patients experienced an improvement in symptoms or neurologic deficits after SRS. 6 (16%) patients experienced adverse radiation effects of worsening seizures or neurologic deficits.

Conclusion

Hypofractionated SRS results in durable local tumor control in WHO grade 1 or suspected grade 1 meningiomas. Limitations to the study are the small size and heterogeneous tumor and treatment characteristics in the sample population. Our next step will investigate the relationship of volume, pathology markers, and dosing regimen to tumor control and adverse radiation effects. 

Background/Objective: Varian’s HyperArc (HA) radiosurgery-specific solution offers highly conformal dose distributions, allowing for the fractionated stereotactic radiotherapy (fSRT) treatment planning of benign brain tumours. These tumours are commonly located in deep-seated eloquent positions overlapping with or near critical optical and neural structures, requiring highly skilled dosimetrists and significant time resources within busy clinical environments. This project aimed to significantly enhance fSRT treatment planning for benign, deep-seated brain tumours by integrating an innovative and novel knowledge-based planning (KBP) prediction model using Varian’s Rapid Plan (RP) solution (KBP-RP). This work presents the robust quality assurance methodology used to refine the model through qualitative, quantitative, and iterative processes to reduce dose significantly and time-efficiently to organs-at-risk (OARs) while maintaining or improving planning target volume (PTV).  

Methods: 51 clinical fSRT patients treated on a Varian Edge HDMLC MV-6FFF LINAC using HA ranging from 5 to 37 fractions between January 2020 and December 2023 were shortlisted in the preliminary KBP model. A qualitative review of OAR contouring and geometrical OAR-PTV relationships was documented for each patient to ensure complexity robustness. A Preliminary noncoplanar HA-specific KBP model was then generated and retrospectively applied to 11 clinical fSRT Plan(_Clinical) patients and compared to the new optimised plans using the preliminary KBP model Plan(KBP_prelim). We evaluated the R50%, Brain-GTV V5, V18, V24 and the maximum dose (D_max) to the Brainstem, Optic Chiasm, Left Optic Nerve, and Right Optic Nerve to determine the consistent efficacy of the KBP model. Any Plan(KBP_prelim) that did not meet the mandatory PTV parameters was reoptimised to ensure clinical suitability.  

Results: Plan(_Clinical) and Plan(KBP_prelim) were compared for each of the 11 fSRT patients; there was a reduction in the Brainstem D_max of 14.1%, while the Optic Chiasm, Left Optic Nerve and Right Optic Nerve all had a reduction of 13.9%, 22.9% and 18.8%, respectively. Plan(KBP_prelim) also demonstrated a R50% reduction of 6.40%, while the Brain-GTV V5, V18 and V24 was reduced by 8%, 7.6% and 8.20%, respectively.  

Conclusion: Integrating a refined KBP-RP prediction model with HA technology substantially reduces OAR sparing while maintaining or improving target coverage for deep-seated brain tumours treated with fSRT. This synergy improves patient outcomes and clinical efficiency through personalised, machine-learned treatment planning. A second stage of the study is now in progress – comparing a further refined second KBP-RP model against the clinical and initial KBP-RP, comparing 19 OARs on all 51 treatment plans trained into the model.  

Purpose 

            Pituitary tumors patients treated with fractionated stereotactic radiation therapy were studied to determine overall survival (OS), progression-free survival (PFS), factors that influence them and complications derived.

Materials and Methods

From 1997 to 2021, 102 patients have been treated with an average age of 55 years (18-81). An extensive database has been created.

Patients treated with cones until 2008, at which time they began to be treated with micromultilaminae and probability of doing IMRT.

The dosimetry was carried out with the planners Iplan‍® of Brainlab until 2016 and later a combination between Elements‍® (contouring) and Eclipse®‍ (dosimetry). The prescribed dose and fractionation was (45-62.1Gy) in 16-31 fractions [one patient 14 Gy in one fx]. With an average volume of planning or PTV: 6.81cc (0.32-11.27).

Tumor types found at similar frequencies: hormone-producing (55.68%) and non-producer (44.32%) adenomas. Being the most manifested growth hormone.

Most common symptom was visual deficit (35.63% of the cases).

Most patients had previous surgeries (93%).

Results

OS and PFS have been studied with a high mean follow-up, up to 15-20 years. OS at 5 years 0.87; tumor PFS at 5 years 0.82; hormonal PFS at 5 years 0.28. Post-radiotherapy ophthalmopathy only 1.4%; post surgery plus radiotherapy 8.8%; ophthalmopathy due to surgery 39.71% and without visual toxicity 50%;

Conclusion

Patients with good prognostic; no direct influence of age or tumor type was found.

The radiotherapeutic effect seems to achieve a great control of the tumor size or volume while the hormonal control is low but easily corrected with substitutive treatment.

Fractionated stereotaxic radiotherapy is safe, with low acute and long-term toxicity including visual or hormonal

The great heterogeneity of the base gives rise to more studies that could also be necessary.

Objective: Patients with deep-seated arteriovenous malformations (AVMs) have a higher rate of unfavorable outcome and lower rate of nidus obliteration after primary stereotactic radiosurgery (SRS). The aim of this study was to evaluate and quantify the effect of AVM location on repeat SRS outcomes.

Methods: This retrospective, multicenter study involved 505 AVM patients managed with repeat, single-session SRS. The endpoints were nidus obliteration, hemorrhage in the latency period, radiation-induced changes (RICs), and favorable outcome. Patients were split on the basis of AVM location into the deep (brainstem, basal ganglia, thalamus, deep cerebellum, and corpus callosum) and superficial cohorts. The cohorts were matched 1:1 on the basis of the covariate balancing score for volume, eloquence of location, and prescription dose.

Results: After matching, 149 patients remained in each cohort. The 5-year cumulative probability rates for favorable outcome (probability difference -18%, 95% CI -30.9 to -5.8%, p = 0.004) and AVM obliteration (probability difference -18%, 95% CI -30.1% to -6.4%, p = 0.007) were significantly lower in the deep AVM cohort. No significant differences were observed in the 5-year cumulative probability rates for hemorrhage (probability difference 3%, 95% CI -2.4% to 8.5%, p = 0.28) or RICs (probability difference 1%, 95% CI -10.6% to 11.7%, p = 0.92). The median time to delayed cyst formation was longer with deep-seated AVMs (deep 62 months vs superficial 12 months, p = 0.047).

Conclusions: AVMs located in deep regions had significantly lower favorable outcomes and obliteration rates compared with superficial lesions after repeat SRS. Although the rates of hemorrhage in the latency period and RICs in the two cohorts were comparable, delayed cyst formation occurred later in patients with deep-seated AVMs.

Optic nerve sheath meningiomas (ONSM) are rare entity which irreversibly leads to vision loss. Treatment options are observation, microsurgery, or standard fractionated radiotherapy. None of these approaches are optimal. With the increasingly available frameless radiosurgery, the possibility of precise radiation is established using a multisession treatment with doses below the tolerance dose of the optic nerve, and sufficient to achieve local control of the disease with no side effects.

Multisession radiosurgey was offered to five patients with ONSM (four females). Patient age ranged from 43 to 73 years (mean 54 years). The diagnosis was based on MR neuroimaging. The tumor originated from the orbital segment of the optic nerve in three patients, from the canalicular segment in one and one patient had bilateral ONSM. The patients underwent thin-slice (1.00- mm-thick) CT scanning and volumetric MR imaging. The median pretreatment tumor volume was 1.96 mL (range, 0.5-5.6 mL). One patient was treated using the Cyberknife S7 machine, four were treated with Linac-based SRS with the Varian Edge RapidArc technique. An 80% prescribed isodose of 25 Gy was delivered in 5 sessions of 5 Gy. Patients were evaluated for tumor growth control and visual function. Mean follow-up duration was 16 months (6 to 25 months) and consisted of MR imaging and visual field and acuity examinations. On MR no changes in lesion size were observed in four patients and minimal regression in one. Visual function was stable in two and improved in three patients. No patients had worsening of visual function. No radiation-induced toxicities were observed. Furthermore, we made a dosimetric comparison between Cyberknife and LINAC-based stereotactic radiosurgery. Both techniques yielded good gross tumor volume coverage and organs at risk sparing. The conformity index was better in RapidArc (1.13 ± 0.35) compared to CyberKnife (1.48 ± 0.43). RapidArc also had a better dose gradient index (73.47 ± 27.98) compared to CyberKnife (55.76 ± 23.94). CyberKnife demonstrated lower maximum doses to some organs at risk such as lens, optic nerve and eye, and RapidArc delivered lower doses for chiasm. For normal brain tissues, V12Gy was lower with RapidArc (3.17 ± 9.69) compared to CyberKnife (5.49 cc ± 10.40).  Tretment time was lower for RapidArc. Conclusion: Multisession radiosurgery for ONSMs is safe and effective. The results from our series, in terms of growth control, visual function improvement, and toxicity, are promising without significant differences between Linac-based and Cyberknife techniques. Further investigations are warranted.

Background: Chondromyxoid fibromas (CMFs) are benign tumors and exceedingly rare in the sellar region. Radical excision is often technically impossible because of their local invasiveness and the presence of complex neurovascular structures. The role of gamma knife radiosurgery (GKRS) as an adjuvant or primary treatment for CMFs in this area has not been reported to date. The goal of this study was to investigate whether GKRS is an effective and safe treatment modality for CMFs in the sellar region.

Methods: Between December 2014 and August 2019, 3 patients haboring CMFs were treated using a Leksell Gamma Knife Perfexion at Gamma Knife Center of Huashan Hospital. Of these, 2 with definitive histopathologic diagnoses after surgery, 1 was diagnosed mainly based on his corresponding MR images and clinical presentation. There were 2 male and 1 female patients with a median age of 39 (range, 36-46) years old. The median tumor volume was 14.26 (range, 4.63-21.76) ml at initial GKRS treatments. Patients received a median prescription dose of 12 (range, 9.5-14) Gy directed to the 48%-50% isodose line (median, 50%).

Results: The median follow-up period after GKRS was 47 (range, 33-60) months. At last follow-up, we report no cases of failure in GKRS for CMFs in the sellar region. All three patients demonstrated a significant reduction in tumor volume. The median tumor volume reduction was 38.99% (range, 9.72%-47.24%) after GKRS treatments compared with the pre-GKRS volume. Post-GKRS clinical improvement was achieved in all three patients (100%). No radiation-induced neurological deficits or delayed complications secondary to GKRS were observed during the follow-up period.

Conclusions: This is the first report to address GKRS for CMFs in the sellar region. Our study showed that GKRS is a useful and safe therapeutic method for CMFs in the sellar region as both a primary and adjuvant treatment. Further studies with long-term follow-up and larger numbers of cases are necessary to optimize the treatment conditions and verify the benefit of this treatment.

Meningiomas are the most common CNS tumors. Recently, an increasing amount of data has emerged regarding the influence of genetic factors on the progression of the disease. Moreover, patients who exhibit biallelic inactivation of Nf2 and Nf2-inactivated schwannomatosis have shown a diminished response to radiation treatment. Additionally, this particular group of patients has a higher incidence of developing meningiomatosis.

In order to study the molecular genetic characteristics of various tumors in nf2-associated schwannomatosis patients (neurofibromatosis type II), a targeted sequencing panel of genes was created. The panel was designed based on the molecular relationships of merlin and also took into consideration known targets of targeted therapy. The selected target genes included mtor, egfr, vegf, map2k1, map2k2, akt1, igf1, kit, erbb2, erbb4, pik3ca, pak1, and pak2. A total of 80 samples were sequenced from 23 patients, including 10 patients with sporadic meningiomas and 13 patients with nf2-inactivated schwannomas and meningiomas. The average number of mapped reads was 1,463,189, with an average coverage of 1447x. 

A total of 740 unique genetic variants were identified, categorized as benign (204), pathogenic (46), variants of unclear clinical significance (477), and artifact (13). The most common pathogenic variants were found in the genes AKT1, EGFR, and ERBB2. It is interesting to note that in the literature, variants in the ERBB2 gene in schwannomatosis patients are primarily described for transitional tumors (schwannoma/neurofibroma) that are usually painful. However, in our sample, variants in this gene were found in vestibular schwannoma and meningioma cells with equal frequency, and none of the cases presented with a pain syndrome such as trigeminal pain. 

Furthermore, while only one driver mutation was found in all samples of sporadic meningiomas in one patient, different gene variants were detected in patients with schwannomatosis, suggesting the need to inhibit previous stages of the signaling pathway. Despite the successful use of VEGF inhibitors to control the growth of vestibular schwannomas and ependymomas in schwannomatosis patients, variants in this gene were only identified in patients with sporadic meningiomas. Nonetheless, these findings also demonstrate the potential use of drugs from this group for some patients with sporadic meningiomas if surgery is not feasible or if the response to radiation treatment is poor.

Introduction: Vestibular schwannoma (SV) is a benign intra or extra-canalicular lesion, which tumor control with radiosurgery is challenged by the choice of an adequate dose and fraccion.

Main objective: To choose different fractionation and equivalent dose, according to the size and proximity of SV to the brain stem. 

Materials and methods: A retrospective analysis was conducted with patients having at least 6 months of follow-up. Nine patients (2016-2023) were treated with five fractions of SRS for a Koos III-IV vestibular schwannoma. Five patients had undergone prior surgery before SRS treatment . SRS was delivered using Linac Novalis Tx or TrueBeam Stx, iPlan v4.5 or Elements Cranial v1.5. Frequency and intensity of tinnitus, dizziness, facial paresis, spasms and trigeminal nerve pain were recorded, before and after SRS, in person or by survey. 

Results: The median tumor volume at the time of SRS was 9.7 cc (4.38-22). Initial symptoms were: 3 anacusis, 2 hypoacusis, 2 tinnitus, 3 dizziness, 2 facial paresis. With a mean follow-up of 34,2 months (6-84), functional hearing was preserved and the intensity and frequency of dizziness were reduced. In resonance imaging 6 had shrinking tumors, 1 showed growth and 2 had stable tumor. 

Conclusions: Fractionation according to tumor size and contact with the brain stem makes it possible to respect the tolerance dose with significant reduction of dizziness and preservation of functional hearing.

Objective: 

Gamma Knife radiosurgery is commonly used in the multimodal management of patients with pituitary adenomas. Regarding the radiation exposure of risk structures such as the optic nerve or the optic chiasm, a safety distance of two millimeters is often considered as crucial in treatment planning. Moreover, varying levels of radiation tolerance have been reported in the literature for organs at risk in close proximity to the pituitary adenoma. The aim of this study is to evaluate the effect of different radiation doses on the critical structures via the endocrinological, ophthalmological and neurological outcome.

Methods:

A retrospective analysis of 139 patients with pituitary adenomas, who underwent at least one Gamma Knife radiosurgical treatment between 2000 and 2022, was performed. The radiation dose to the defined critical structures as well as the minimal distance between the pituitary adenoma and these structures were measured with the Elekta Planning System. 

Results:

The majority of the study population (134/139, 96%) underwent a previous surgical removal of the pituitary adenoma. The pituitary adenomas were hormone-active in 92/139 (66%) patients. The median treatment volume was 4.6 cm3 (0.5-16.7). In 3/139 (2%) patients, a compression of the optic chiasm or optic nerve could be observed. 

Of 130/139 (94%) with available pre-radiosurgical planning data, the maximal radiation doses on the optic chiasm were 6.2 Gy (1.5-16.3). After Gamma Knife radiosurgical treatment, the majority of patients (95%) with radiological follow-up had a decreased tumor volume. Furthermore, the majority of the patients (96%) did not have any worsening of the ophthalmological deficits. 

Conclusion:

Radiosurgical treatment is a safe therapy option for pituitary adenoma patients without worsening of ophthalmological deficits. 

Objective:

Gamma Knife SRS is an established technique in the treatment of Brain AVM,s. However radiosurgery for AVM is still associated with a risk of developing new neurological deficits, which may be permanent. We report our experience with integrating stereotactic diffusion tensor imaging (DTI) tractography into treatment planning for Gamma Knife SRS for Arteriovenous Malformations.

Methods:

Stereotactic DTI studies were performed in 37 (41 treatments) patients who underwent GKRS for AVM over a four year period.

Age range 18-77 years Female 14pts : Male 23 pts.

Marginal dose 18-25 Gy, 6 retreatments, 5 staged treatments, 26 primary treatments 90-99% coverage, TV 0.057 – 15.9cc

DTI images were obtained at the time of standard GKRS protocol MRI (T1 and T2 weighted) for treatment, with the patient's head secured by a Leksell stereotactic frame. DTI was performed with diffusion gradients in 32 directions and coregistered with the volumetric T1-weighted study. DTI post-processing by means of commercially available software allowed tensor computation and the creation of directionally encoded color, apparent diffusion coefficient & fractional anisotropy mapped sequences. The visualized critical tracts were exported as a structural volume and integrated into GammaPlan as an “organ at risk” during during shot planning and subjected to dosimetry.

Results:

DTI allowed visualisation & dosimetry of eloquent white fibre tracts during treatment planning.

The Optic Radiation was most frequenty involved in 26 cases, Cortiso-Spinal Tract in 12 cases and the Arcuate Fasiculus in 6 cases.

The 12 Gy Vol ranged from 0.221 – 45.65 cc. One patient with mesial temporal AVM developed delayed worsening of a pre-existing hemianopia & another with AVM required steroids for cerebral swelling, One patient died of natural causes during the follow up period.

No other neurological deficits due to radiation were recorded at follow-up.  

Conclusions:

Stereotactic Tractography represents a promising tool for preventing GK-SRS complications by reduction in radiation doses to functional organs at risk, including critical cortical areas and subcortical white matter tracts & further increase our knowledge of critical cerebral structure radiation tolerances to better improve the therapeutic potential and safety of SRS for AVMs.

Brain Tumour Surgery in the Context of Evolution in Radiosurgery

Objective: 

highlight brain tumour patient selection for radiosurgery vs. surgery in the two most frequent brain tumour types: metastasis and meningioma.

Review up-to-date surgical and radiosurgical techniques.

Introduction: 

The use of GKRS in brain metastasis and meningioma has increased worldwide, with high-impact evidence on its safety and efficiency with new modern techniques.

The variations in international standards widened the gap where, in some places, GKRS is overused and, in some places, not applied to brain tumors. In this presentation, I will try to review the current evidence and up-to-date techniques.

Methods: 

updated literature review on GKRS in meningioma and brain metastasis (solitary)

a retrospective review of some surgical cases.

Results:

The grey zone is wide when it comes to patient selection for surgery vs. radiosurgery for the two most common brain tumours.

GKRS in brain metastasis can be used as a standalone option or before surgical resection and in the resection cavity. Tumour size, number of metastases, primary tumour origin, systemic disease, and KPI are very important factors in decision-making.

Surgical resection of brain metastasis, either enbloc or piecemeal removal Enbloc resection has shown some superiority.

GKRS in meningioma offers an excellent option as a standalone option or for a residual tumour after surgery with evidence of progression. Tumour size, the presence of a neurological deficit, and meningioma grade are crucial in decision-making. Fractionated GKRS offers a safe option for tumours with close proximity to ctrical structures like the optic pathway and brain stem.

Surgical resection should aim for Simpson grade zero when possible, and the key surgical steps include devascularization of the tumour first, followed by central debluking and degloving from the surroding neurovascular structures and brain. Minimally invasive approaches, including navigational-guided craniotomies, keyhole approaches, and endcscopic approaches, should be applied when feasible.

Conclusion: 

Radiosurgery for meningioma and brain metastasis is an important aspect of management. A multidisciplinary approach is preferred to achieve better outcomes.

Introduction: Cavernous sinus meningiomas (CSMs) remain a surgical challenge due to the intimate involvement of their contained nerves and blood vessels. Stereotactic radiosurgery (SRS) is a safe and effective minimally invasive alternative for the treatment of small- to medium-sized CSMs.

Objective: To assess the medium- to long-term outcomes of SRS for CSMs with respect to tumour growth, prevention of further neurological deterioration and improvement of existing neurological deficits. This multicentric study included data from 15 European institutions.

Methods:We performed a retrospective observational analysis of 1222 consecutive patients harbouring 1272 benign CSMs. All were treated with Gamma Knife stereotactic radiosurgery (SRS). Clinical and imaging data were retrieved from each centre and entered into a common database. All tumours with imaging follow-up of less than 24 months were excluded.

Results:Detailed results from 945 meningiomas (86%) were then analysed. Clinical neurological outcomes were available for 1042 patients (85%). Median imaging follow-up was 67 months (mean 73.4, range 24-233). Median tumour volume was 6.2 cc (+/-7), and the median marginal dose was 14 Gy (+/-3). The post-treatment tumour volume decreased in 549 (58.1%), remained stable in 336 (35.6%) and increased in only 60 lesions (6.3%), yielding a local tumour control rate of 93.7%. Only 27 (2.8%) of the 60 enlarging tumours required further treatment. Five- and ten-year actuarial progression-free survival (PFS) rates were 96.7% and 90.1%, respectively. Tumour control rates were higher for women than men (p = 0.0031), and also for solitary sporadic meningiomas (p = 0.0201). There was no statistically significant difference in outcome for imaging-defined meningiomas when compared with histologically proven WHO Grade-I meningiomas (p = 0.1212). Median clinical follow up was 61 months (mean 64, range 6-233). Permanent morbidity occurred in 5.9% of cases at last follow-up.

Conclusions: Stereotactic radiosurgery is a safe and effective method for treating benign CSM in the medium term to long term.

Estimation of the minimum value for the gradient index (GI) in Vestibular Schwannomas planning considering the sphericity degree using Leksell Gamma Plan^â

Authors: Saraiva, C. W. C.; Folador, B. C. F.; Da Rosa, L. A. R.; Gorgulho, A. A.; De Salles, A. A.;

Introduction: The sphericity degree is defined as a measure of how similar the shape of an irregular volume (V) is to that of a sphere. In vestivular schwannoma treatments, the volumes can vary significantly, as well as the sphericity degree. In addition to these geometric characteristics, its proximity to the cochlea requires a high dose falloff. Therefore, estimating a minimum possible value for these plans helps to identify a metric for the evaluate the quality of the plan obtained. 

Methodologia: For the sphericity degree, the equation used was, j = (V_TV / V_{sphere circ})^1/3 where V_TV is the irregular target volume and V_{sphere circ} is the volume of the smallest sphere that circumscribes the target volume (TV).

To calculate the gradient index, the ratio between the volume of the isodose of 50% of the prescription and the volume of the prescription isodose is used. These volumes were obtained from the Leksell Gamma Plan planning system.

To evaluate dose falloffs, plans called reference plans were carried out using the TPS, Leksell Gamma Plan® (LGP), version 10.0. These reference plans were defined using the following steps: (i) calculate the diameter d_eq, of an equivalent sphere – a sphere that has a volume equal to the volume of the target; (ii) delineate this sphere within a Alderson® anthropomorphic phantom head; (iii) define this equivalent sphere as the target volume in the TPS LGP; (iv) define planning parameters; With these results, it was possible to evaluate, in a comparative way, the GI obtained in the treatment plans with the GI obtained in the reference plans.

Results and discussion: The average value of the sphericity degree obtained was 0.69±0,10, with the lowest value equal to 0.50 and the highest value equal to 0.9. Regarding the evaluation of the gradient index, it was possible to observe that this parameter, under the reference conditions (spherical target volume, anthropomorphic phantom phantom), assumes values lower than 3, thus corroborating the GI = 3 metric. Thus, the minimum values for the gradient index ranged from 2.44 to 2.90.

Skull base perioptic meningiomas are challenging for stereotactic radiosurgery (SRS). The therapeutic window between tumor control and normal tissue complication is extremely narrow in these tumors, especially of large volume and/or in close proximity to the optic apparatus (OA). To minimize the risk of radiation toxicity, we optimized our SRS plans in terms of both steeper dose fall-off and dose-volume constraints for OA and delivered hypofractionation treatment.  

Thirty-one patients had been treated with hypofractionated SRS using the CyberKnife for perioptic meningiomas > 10 cm³ in volume (median 18.9 cm³). Tumor locations were cavernous sinus (n=7), petroclival (n=6), and tentorial edge (n=6). Optimization in SRS planning was carried in two aspects: 1) for steeper dose fall-off, multiple virtual shells outside the target were introduced and appropriate dose limits (formulated from our own Gamma Knife data) were applied; and 2) to minimize the risk of optic neuropathy, dose-volume constraints for OA (from AAPM TG101) were applied. SRS was delivered in five daily fractions with a median cumulative dose 27.8 Gy.

With a median follow-up of 33 months, tumor control was achieved in 28 of 31 patients (90.3%). Treatment response on MRI included partial response (volume decrease > 20%) in 17 patients, stable in 11, and progression (volume increase > 20%) in 3. Neurological symptoms improved in 10 patients, unchanged in 20, and worsened in 1.

Our current results show a promising role of hypofractionated SRS with optimization in steeper dose fall-off and dose-volume constraints for OA for large-sized skull base perioptic megningiomas in terms of both tumor control and neurological outcomes.

Central AVMs are challenging group of vascular  Malformations. Radiosurgery alone or in combination with endovascular approach seems to be the best available treatment modality right now. However there is inherent risk of edema and radiation necrosis risk involved.

We reviewed our patients with central AVM with a minimum follow up of 2 years retrospectively. The machine learning deep neural network applied to look for risk factors for adverse reactions in these cases.

A total of 35 patients receiving primary Gamma knife were included in the study. They were divided into pure thalamic, thalamo peduncular and brainstem lesions. 

It was observed that the trickiest lesions are those located in thalamopeduncular area and low dose staged Gamma knife is the best approach.

Purpose: This study aimed to evaluate the dosimetric accuracy of Cyberknife (CK) for benign perioptic tumor using patient-specific head phantom.

Methods: A patient specific head phantom was fabricated using a 3D-printer to ensure dosimetric equivalence with the actual target regions of a benign perioptic tumor case treated via Cyberknife radiosurgery. A head phantom quality assurance (QA) plan was produced using the original CK contour set encompassing the target and optic nerve. The head phantom, equipped with Gafchromic EBT3 film, was subjected to irradiation using the Cyberknife 6D skull tracking method. The dose distributions calculated by the MultiPlan Treatment Planning System (version 5.6) were compared to the measurements obtained through film dosimetry using the gamma analysis method. The CK treatment manipulator utilized 6D corrections data obtained from orthogonal X-ray images to automatically deliver radiation to the displaced position of the target. To access the accuracy of the 6D skull tracking, the couch table was adjusted by translating it by 1-5mm and rotating it by 1 degree prior to beam delivery, and the resulting beam irradiation was examined.

Results: All cases achieved passing rates that exceeded the acceptable threshold of 80% and 90% for the 2%/1 mm and 2%/2 mm criteria, respectively. Among the ten cases (case 1 - 10) with less than 2 mm shift and 1 degree rotation, the calculated gamma index with pass criteria of 2%/1 mm and 2%/2 mm averaged at 84.71 ± 1.73% and 94.12 ± 0.75%, respectively. For the other two cases (case 11 and case 12) with a 5 mm shift in both the right and left directions, the average gamma pass rates using the same criteria were 81.09 ± 0.74% and 91.03 ± 0.21%, respectively.

Conclusions: Dosimetric verification using patient-specific head phantom was successfully implemented as an evaluation method for CK perioptic tumor radiosurgery delivery with 6D skull tracking system.  

Introduction: Stereotactic radiosurgery (SRS) is an important management option for patients with small- and medium-sized vestibular schwannoma (VS). Its use in the treatment of large tumors, however, is still being debated.

Objectives:  To assess the potential role of SRS in larger VS.

Materials and Methods: Between 2016 and 2023, 35 patients diagnosed with unilateral VS greater than 25mm, underwent SRS.  A total dose prescribed to the tumor volume ranged 11-35Gy in 1-5 fraction, delivered with linear accelerator with image-guided radiotherapy (IGRT) system.  Acute and chronic toxicity was evaluated according to the International Criteria for Adverse Events (CTCAEv4.0).  In the statistical analysis, Pearson chi-square test, was used. 

Results: The median follow-up was 36 months (6-50 months), median age 50 years (20-77), 58% of the patients had prior surgery, median irradiated tumor volume (GTV) 8 cc. (2-45cc), 86% of patients were Koss 3 and 14% Koss 4.

At the first planned imaging follow-up at 6 months, tumors 30% were slightly expanded with central radionecrosis, 52% were stable in size, and 18% were smaller. In the last follow-up none presented tumor regrowth after radiosurgery.

As regards the evolution of related symptoms post SRS treatment, hearing loss was observed in all patients, tinnitus increased from 31% to 35% (p=0.17). Decreases in vertigo from 58% to 31% (p=0.05), and facial neuropathy from 46% to 12 % (p=0.0006).  Two (6%) patients developed temporary symptomatic trigeminal sensory dysfunction developed, and in 1(3%) patient mild facial weakness. These patients had a previous resection or postsurgical neurological dysfunction.

Conclusions: although microsurgical treatment remains the primary management choice, in selected patients with low comorbidities, most larger vestibular schwannomas without significant mass effect can be managed satisfactorily with SRS. 

Introduction:

In Cavernous Malformations, recurrent haemorrhage is common after an initial bleed. Rates of recurrent haemorrhage in supratentorial and brainstem lesions are 5% and 21% per year, respectively and can be associated with devastating consequences. The aim of this retrospective study is to highlight the efficacy of Gamma Knife Surgery (GKS) in managing Cavernous Malformations. 

Methods:

Data from 11 symptomatic cavernous malformation patients undergoing GKS at Hospital Universiti Kebangsaan Malaysia (HUKM) from the beginning of 2020 to 2023. The patient’s treatment plan and case notes were retrospectively reviewed. The mean and median cavernoma volumes before GKS treatment were 2140mm³ and 1222mm³  respectively (range: 850mm³ – 1156mm³). The median tumour margin dose was 14Gy (range 12Gy – 16Gy). Median follow up was 12 months (range: 6 – 21 months).

Results:

Among the 11 patients, two experienced at least one episode of pre-GKS seizure. Post-GKS, mean and median cavernoma volumes dropped to 1263mm³ (59% reduction) and 889mm³ (73% reduction), respectively. Five patients showed no change in size. There were no recurrent haemorrhages, seizures, or radiation adverse effects during the 11 person-years of follow up. 

Conclusion:

GKS demonstrated significant clinical improvement in all 11 symptomatic patients. No recurrent haemorrhages or seizures were observed. A comprehensive evaluation through a systematic review with a larger sample size is warranted.

Abstract

Purpose: Skull base meningiomas represent a very challenging pathology due to relatively difficult surgical access. In contrast, stereotactic radiosurgery (SRS) proved to be an effective and more secure treatment technique based on the greater accuracy in delivering precise focused radiation into the target, sparing at the same time healthy surrounding tissues.

Methods and results: Our study, based on almost 20 years of experience in delivering SRS treatments using various models of Leksell Gamma-Knife units, reports a high tumor control rate for complex-shaped skull base meningiomas close to critical structures. We retrospectively evaluated the risk factors and complications after high-dose irradiation in patients undergoing single-fraction radiosurgery combined with clinical imaging criteria established using MRI scans (in T1 weighted imaging with gadolinium and the edema in T2 weighted sequences).

The mean volume of the tumors was 18.6 cubic centimeters (only tumors with a volume in excess of 15 cubic centimeters were included in the study). The median administered marginal dose was 12.5 Gy. Mean imaging follow-up was 112 months. Tumor control rate was not influenced by sex, age, tumor site, neurological status of the patient or irradiated volume, even though larger meningiomas are associated with poor long-term local control in most published series.

The long-term follow-up data indicates tumor control in 88,5% of patients after 10 years, with low incidence of complications.

Conclusions: Current practice shows a slight potential increase in the incidence of meningiomas, the superiority of the individual techniques needing to be confirmed in prospective and methodologically rigorous studies with at least 20 years of follow-up.

Intracranial Paragangliomas are rare neuroendocrine tumors arising from paraganglia, and given the morbidity and mortality associated with surgical treatment, is a great challenge for Neurosurgery. The use of Radiosurgery is a alternativ to surgey,  with excellent results, but the lack of long-term follow-up still left in doubt its effectivenes.

OBJECTIVE: To present the results of local lesion control and toxicity in a series of patients undergoing treatment with exclusive use of focal ionizing radiation, be it Radiosurgery (RS), Fractionated Stereotactic Radiotherapy (FSRxT) or Hypofractionated Stereotactic Radiotherapy (HFSRxT) and who were followed for a minimum of 60 months after treatment.

MATERIAL AND METHODS: A retrospective analysis in the medical records of our hospital, selecting patients with intracranial Paragangliomas who underwent SR, FSRxT or HSRxT) between 2000 and 2023. A Linear Accelerator (LINAC) was used associated with Micro-Multileaf collimators and dedicated software. To enter the study, these patients had a minimum follow-up of 60 months. We evaluated local control as well as treatment toxicity.

RESULTS: Among 2930 patients treated, 32 patients were selected. With a mean follow-up of 85 months, 68% of patients had a reduction of the lesion when compared to treatment and 32% maintained stability of the lesion. No patient followed had progression of the disease, but 1,  that had bilateral lesion, and the untreated lesion progressed 3 years later, when it was treated there and subsequently reduced its volume. No patient presented clinical worsening associated with toxicity in the brain tissue or cranial nerves involved.

CONCLUSION: Treatment with the use of focal ionizing radiation, whether SR, FSRxT or HSRxT, is an extremely safe and effective procedure in the management of paragangliomas regardless of their volume. Even in giant tumors should be the first therapeutic option and surgery should be limited to selected cases

Background: Silent corticotroph pituitary adenomas (SCAs)/ neuroendocrine tumors (PitNETs), exhibit heightened clinical aggression, predisposing them to higher recurrence rates and reduced treatment responsiveness compared to other subtypes. These patients often require comprehensive treatment, and Cyberknife radiosurgery (CKRS) may become a vital postoperative therapy for relapse.

Objective: This study aimed to investigate the efficacy and safety of Cyberknife radiosurgery in recurrent aggressive PitNETs. 

Methods: We conducted a retrospective study involving patients who experienced postoperative recurrence and were treated with CKRS at our medical center. We present patient outcomes encompassing alterations in tumor size assessed through radiological evaluations, along with recorded adverse events such as newly diagnosed visual impairment and pituitary dysfunction.

Results: Fourteen patients underwent CKRS between 2017 and 2023. All patients received a pathological diagnosis confirming PitNETs characterized by positive immunohistochemistry for t-pit or ACTH markers. Among the series, 50%(n=7) patients underwent dose-staged CKRS, whereas the remaining received fractionated CKRS. The median fractionation regimen encompassed 3, with varying ranges from 2 to 5. Single-dose parameters ranged from 4 to 10.2Gy. The mean tumor volume before treatment was 16.39cc. The average follow-up period was 27.1 months, 95%CI [14.5, 39.7]. Following a 5-year post-CKRS, one patient demonstrated complete remission(CR), and no recurrence to date. 50%(n=7) of total patients had partial response (PR). In a specific case, the tumor volume exhibited an increase 4 months after CKRS, leading to a surgical intervention. The tumor response was quite similar between patients who underwent 2-staged CKRS and all other patients. Notably, the subgroup that underwent staged CKRS presented with larger tumor volumes(P=0.05). None of the patients developed newly onset pituitary dysfunction or visual defect following CKRS.

Conclusion: Fractioned CyberKnife radiosurgery demonstrates effective tumor control for aggressive pituitary tumors experiencing postoperative recurrences, representing a safe and promising therapeutic option. Staged CKRS is considered viable when dealing with large lesions or those in close proximity to critical organs.

Background: The optimal postoperative management of WHO grade 2 meningiomas is controversial, because target definition is difficult with standard-of-care contrast-enhanced MRI.

Patients with subtotal resections are generally offered either radiotherapy or radiosurgery. We evaluated the local control (LC) probability following [68Ga]-DOTATATE PET/MRI guided radiosurgery in patients with subtotally resected WHO grade 2 meningiomas.

Methods: In this institutional review board-approved, HIPAA compliant study, patients with a history of clinically suspected or pathology-proven meningioma were prospectively enrolled into a registry after undergoing DOTATATE PET/MRI. Seventeen consecutive patients with biopsy-proven WHO grade 2 meningiomas were identified from the registry for further analysis. Patients underwent [68Ga]-DOTATATE PET/MRI with concurrent contrast-enhanced brain tumor protocol MRI. Co-registered PET and gadolinium-enhanced T1-weighted MRI series were fused to a simulation CT for radiosurgery planning. 16/17 (94%) patients received fractionated radiosurgery while 1 patient (6%) received single-fraction radiosurgery. The residual meningioma gross target volume (GTV) was identified from both the post-contrast T1-weighted MRI and the [68Ga]-DOTATATE PET. The PET GTV was defined as having a SUV ratio (SUVR) in reference to the superior sagittal sinus blood pool of 3 or greater. A 1.0 mm isotropic planning target volume (PTV) margin was added to the combined PET/MRI GTV. Postoperative radiosurgical treatments were (Gy/fractions, N (patients) listed in parentheses): 35/5 (N = 10), 30/5 (N = 4), 25/5 (N = 1), 28.5/3 (N = 1), 18/1 (N = 1). Follow-up contrast-enhanced MRI was performed per standard-of-care and the development of new nodular contrast enhancement on surveillance MRI was defined as progression based on RANO criteria and confirmed with DOTATATE PET.

Results: The mean age was 56 (range 39-75) months and the mean follow-up time after radiosurgery was 25 (range 5-48) months. 10/17 patients (59%) were female. 11/17 patients (65%) achieved LC after [68Ga]-DOTATATE PET/MRI-guided radiosurgery for their biopsy-proven WHO grade 2 meningiomas. Six patients (35%) had progression after [68Ga]-DOTATATE PET/MRI guided radiosurgery and underwent a second course of [68Ga]-DOTATATE PET/MRI guided salvage radiosurgery. Five of these six patients (83%) achieved LC after salvage radiosurgery. Thus, 16/17 patients (94%) achieved LC after 1 or 2 sessions of PET/MRI-guided radiosurgery. One of the six patients who progressed (17%) had multiple recurrences treated with additional courses of radiosurgery and [177Lu]-DOTATATE radionuclide therapy.

Conclusions: An excellent overall rate of tumor control is achievable (when salvage radiosurgery is included) with the addition of [68Ga]-DOTATATE PET to MRI-based radiosurgery planning for WHO grade 2 meningiomas.

Background: Somatostatin receptor 2 (SSTR2) is a highly sensitive and specific meningioma biomarker that can be imaged with [68Ga]-DOTATATE. [68Ga]-DOTATATE PET/MRI has demonstrated clinical utility for meningioma diagnosis, surgical and radiation planning, however its effect on clinical outcomes is less well understood. The management of gross-totally-resected (GTR) WHO grade 2 meningiomas is controversial, with ongoing randomized clinical trials mounted to determine the benefits of postoperative fractionated irradiation of the resection cavity versus active surveillance. We hypothesized that the determination of GTR by DOTATATE PET/MRI would increase the progression-free-survival (PFS) probability in patients subsequently managed with active surveillance compared to historical data of patients with GTR determined by MRI alone.  

Methods: 27 consecutive patients enrolled into our prospective observational registry met inclusion criteria of (1) WHO-2 meningioma, (2) postoperative brain PET/MRI or PET/CT (with contemporaneous brain MRI) demonstrating GTR, (3) postoperative management with active surveillance only. Postoperatively, patients were followed with serial standard-of-care MRI. Recurrences were determined using RANO criteria and Kaplan-Meier analyses were performed to determine PFS probabilities.

Results: 27 subjects met inclusion criteria. MRI follow-up data were available for a mean of 17 (range: 3-49) months. We found PFS of 100% at 2.5 years and 80% at 4 years.

Conclusions: We found that DOTATATE PET/MRI-determined GTR and subsequent active surveillance resulted in excellent PFS in patients with WHO grade 2 meningiomas. Our findings suggest that DOTATATE PET/MRI can increase the diagnostic certainty of a GTR in WHO grade 2 meningioma compared to MRI alone, thereby increasing the PFS probability for patients subsequently managed with active surveillance. DOTATATE PET/MRI thus has the potential of changing clinical practice and outcomes in this patient population.

Background: 

Cerebral meningiomas represent approximately 40% of primary brain tumors. They can present challenges in managent requiring combination of treatment modalities such as endovascular embolization, surgery and radiosurgery. Gamma Knife radiosurgery has proven successful as a non-invasive high precision treatment tool for complex cases not amenable to surgery.

Objective: 

To evaluate the safety and effectiveness of Gamma Knife radiosurgery for intracranial meningiomas focusing on the single center experience of the Puerto Rico Medical Center.

Methods: 

Retrospective review of 148 patients with 158 brain meningiomas treated with single fraction (N=132) and dose-fractionated (N=16) Gamma Knife radiosurgery from 2010 to 2022. Treatment efficacy was evaluated based on tumor volume reduction or stabilization rates. Procedure safety was assessed based on frequency and severity of adverse radiation effects. Follow-up ranged from 2 months to 10 years.

Results: 

Tumor control was adequate as evidenced by tumor volume reduction and/or stabilization in the majority of cases. Adverse effects were similar to those reported in the literature, consisting of peritumoral adverse radiation effects that responded to short course of steroids and seizure medications when indicated.

Conclusion: 

Gamma Knife radiosurgery for cerebral meningiomas represents a safe and effective alternative for either simple or complex cases. Tumor control rates were adequate as evidenced by tumor volume reduction and/or stabilization with minimal adverse effects that were manageable with medications. Dose fractionation shows promising results for cases with high tumor volumes or close to eloquent areas.

Objective: The contemporary approach to treating cerebral arteriovenous malformations (AVMs) integrates microsurgery, embolization, and stereotactic radiosurgery (SRS). While single-fraction SRS is the standard for AVM treatment, challenges arise with large AVMs (>10 cc), particularly in eloquent brain areas, where the required high doses (18-24 Gy) may pose safety concerns. Hypofractinateded radiosurgery emerges as a solution to reduce radiation exposure to critical structures while ensuring effective AVM obliteration. This study aims to assess the safety and efficacy of hypofractinated SRS for large AVMs based on our clinical experience.

Methods: From 2016 to 2022, 10 patients (7 women, 3 men) with large AVMs (>10 cc) underwent stereotactic radiosurgery using the CyberKnife M6 at SRC Sigulda, Latvia. Among them, 8 had a history of AVM-related hemorrhage. 6 patients underwent endovascular AVM obliteration using Onyx, with incomplete nidus shutdown or recanalization. Symptoms included headaches (9 patients), seizures (5 patients), and sensory/motor deficiencies (4 patients). SRS comprised single-fraction CyberKnife at 20 Gy for 3 patients and hypofractionated SRS (2 fractions, total dose 24 Gy) for 7 patients.

Results: Patients received post-treatment assessments at 6, 12, and 24 months, involving magnetic resonance imaging (MRI) and MRI angiography. Digital subtraction angiography (DSA) was performed for four patients at the 24-month mark. 5 patients (2 from single-fraction SRS, 3 from hypofractionated dose-staged SRS) displayed complete AVM obliteration. All patients maintained stable clinical conditions without signs of post-radiation toxicity (grade 2-3). 2 patients experienced recurring AVM bleeding six months post-treatment.

Conclusions: Dose-staged SRS emerges as a safe strategy for treating large AVMs, particularly in eloquent brain regions, with minimal risks of post-radiation toxicity and hemorrhage post-SRS. However, achieving statistically reliable levels of obliteration warrants ongoing observation and research.

Introduction: Stereotactic radiosurgery (SRS) stands as a crucial therapeutic avenue for individuals grappling with cavernous sinus meningiomas (CSM). This clinical study delves into a retrospective examination of the efficacy of SRS in treating CSM, employing diverse radiosurgical techniques.

Materials and Methods: Thirty-two patients (10 males, 22 females) with CSM underwent stereotactic radiosurgery using the "Trilogy + BrainLab" linear accelerator (LINAC). Tumor volumes ranged from 2.8 cc to 20.9 cc (median, 9.1 cc). In the LINAC group, 75% of patients received SRS exclusively, while 25% underwent prior surgery. Additionally, 13 patients (6 males, 7 females) underwent CyberKnife (CK) SRS, with a median tumor volume of 13.6 cc. In the CK SRS group, 30.7% of patients had undergone surgery before. Marginal doses for LINAC SRS ranged from 11 Gy to 12.5 Gy (median, 12.1 Gy), while CK SRS utilized doses of 18-25 Gy in 3-5 fractions. The median follow-up duration was 42 months (range, 30-60 months).

Results: Follow-up assessments revealed a reduction in tumor size in 46.8% of LINAC patients, with no further growth observed in 53.2% of cases. In the CK group, 38.4% experienced a decrease in tumor size, while 53.8% maintained a stable tumor size. Improvement in neurological condition was noted in 35.5% of patients in both groups, with no worsening observed in the remaining 64.4%. None of the patients reported post-radiation toxicity of grade 2-3.

Conclusions: SRS emerges as an effective treatment modality for CSM, demonstrating comparable outcomes across various radiosurgical techniques. Whether utilizing LINAC or CK, SRS provides robust tumor control with no discernible difference in the quality of life outcomes for patients with CSM

Introduction: 

In the present study, we systematically review the literature describing outcomes of CyberKnife radiosurgery (CKRS) for vestibular schwannoma (VS), with particular focus on tumor control, hearing preservation, and dosing schema. 

Methods: 

We queried the three databases to identify all primary retrospective studies reporting local tumor control and hearing preservation rates following CKRS for VS. Studies meeting inclusion/exclusion criteria were reviewed to extract data on treatment paradigms, hearing outcomes, and local control. Pooled random effects meta-analysis of long-term tumor control and hearing preservation rates were performed.

Results:

Fifteen studies were included in the final analysis. In aggregate the studies comprised 2,018 treated patients (mean age 60.2 years; 52% female), of whom 64 had neurofibromatosis type 2 (NF-2) and the remaining had sporadic lesions. Three hundred nine patients had undergone prior treatment – surgical resection and/or radiosurgery and mean follow-up for the entire cohort was 40.0 months. Dosing paradigms varied across included studies without any identifiable trends in total dose, marginal dose, or fractionation schema over the range of years studied. Marginal dose ranged from 1.9-25.78 Gy. Published schema ranged from 1-5 fractions, and dose and fraction regimens described in studies published prior to 2014 and those published thereafter appeared comparable. Isodose lines were reported in 13/15 studies and ranged from 55%-95%. Average local control across all studies was 96.0% (95% CI: 95%-98%) with no significant difference in control rates being noted between the pre-2014 (OR 0.96; 95% CI [0.94, 0.99]) and post-2014 cohorts (OR 0.96; 95% CI [0.95, 0.98]. As demonstrated by the funnel plot for tumor control, asymmetry is readily apparent, suggesting the potential for publication bias. Additionally, the I² was 57% (p<0.001), suggesting the potential for significant heterogeneity across studies. Hearing outcomes were measured using the Gardner-Robertson classification system in 8 studies and the American Academy of Otorhinolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification system in seven. For patients with serviceable pre-treatment, 73% had preserved hearing at last follow-up (95% CI 66%-81%). Significant heterogeneity was noted between studies in hearing preservation rates (I²=89%, p<0.001). Comparison of outcomes between the pre-2014 (OR 0.82; 95% CI [0.74, 0.90]) and the post-2014 era (OR 0.66; 95% CI [0.55, 0.79]) showed a non-significantly higher rate of hearing preservation than the pre-2014 cohort.

Conclusions:

The present meta-analysis shows CyberKnife radiosurgery offers high rates of local control and hearing preservation in patients undergoing SRS for vestibular schwannomas. 

68 patients with newly diagnosed Vestibular Schwannoma (VS) between 2013 and 2016 were randomized to upfront Gamma Knife Radiosurgery (GKRS) or conservative management (wait-and-see approach). Patients in the GKRS-group were given a state-of the art VS-treatment with Gamma Knife Perfexion or Icon at Karolinska University Hospital with a dose prescription of 12 Gy and optimization of dose to organs at risk, coverage and selectivity. All patients in both groups received 1-, 2-, 3- and 5-year follow-up with T1-weighted FSPGR images of 1mm slice thickness by the latest General Electric MRI system. Tumor volumes were identified on all images by experienced GK-users. All follow-up images were discussed in a multi-disciplinary committee and patients in the conservative group with significant tumor-growth were scheduled for a GKRS-treatment. Differences in tumor volume dynamics between the two groups at each follow-up was analyzed using Wilcoxon Rank Sum Test.

35 patients were randomized to GKRS whereas 33 patients to the conservative group. Both groups were balanced with respect to age, gender and tumor volume at baseline. 15 patients in the latter group had significant tumor growth on follow-up imaging which disqualified them from further conservative treatment: 11 of these at 1-year, 3 at 2-year and 1 at 3-year follow-up, respectively. Average change in volume (compared to baseline) for the GKRS-group was 6%, -11%, -14% and -24%, at 1-, 2-, 3- and 5-years, respectively, whereas the volume dynamics in the conservative group was 91%, 32%, 17% and -1%. Significant difference in the follow-up tumour-volumes between the groups was identified for all follow-up periods: p-values 0.0001, 0.0002, 0.0054 and 0.0398 for 1-, 2-, 3- and 5-year follow-up, respectively.

This randomized controlled study shows that there is a strong statistical difference in the follow-up tumour-volume between the two groups. This significance weakens with increasing follow-up time (by increasing p-values) which is assumed to be due to reduction of the conservative group by patients with fast tumours growth (consisting of 45% of the initially conservative group) leading to a selected group of slow- and non-growing tumours. This work also demonstrates that newly diagnosed VS can be seen as a mixture of three groups with respect to tumour-growth: 45% fast-growing tumours, 33% slow/negligibly-growing tumours and 21% with negative tumour-growth (average -34%) at 5-year follow-up. Developing means to identify the projected tumour-growth of newly diagnosed VS can potentially have an impact on treatment selection, treatment time guarantee and follow-up duration.

BACKGROUND: The difference in tumor control rate after stereotactic radiosurgery (SRS) between neurofibromatosis type-2-associated vestibular schwannomas (NF2-VSs) and sporadic vestibular schwannomas (S-VSs) has been debated and is yet to be completely elucidated. To address this issue, the Korean Gamma Knife Radiosurgery Society conducted the first nationwide, multicenter, retrospective study (KGKRS-21-001).

METHODS: A total of 4,718 patients treated with SRS for VSs were enrolled from 13 nationwide institutes. NF2-VS cases were matched with S-VS cases at a ratio of 1:1 using propensity scores for age, tumor volume, and marginal dose. After matching, 122 cases in each group of NF2-VS and S-VS were selected and analyzed.

RESULTS: There were no statistically significant differences in age, tumor volume, or marginal dose between the NF2-VS and S-VS groups. The overall matched cohort analysis showed that the tumor control rates at 1, 3, and 10 years after SRS were 93.3%, 87.7%, and 80.7%, respectively. The difference in tumor control rates between the two matched cohorts was not statistically significant (p=0.63). In the subgroup analysis of NF2-VSs, age ≤20 years was a significant negative factor related to tumor control (p<0.001). However, there was no significant difference in tumor control with respect to age in the S-VS cohort (p=0.78).

CONCLUSION: There was no difference in tumor control between NF2-VSs and S-VSs after SRS. However, patients younger than 20 years of age, especially in the NF2-VS cohort, showed significantly poorer tumor control after SRS compared with older patients.

Introduction

The mechanism of hearing loss following stereotactic radiosurgery (SRS) for vestibular schwannomas (VSs) remains unclear. There is conflicting evidence regarding cochlear nerve damage by transient volume expansion of VSs after radiosurgery and radiation-induced cochlear damage. This study aimed to investigate whether there is a specific patient population that can achieve definite hearing preservation after SRS for VSs.

Methods

A total of 40 consecutive patients with sporadic unilateral intracanalicular VSs and serviceable hearing (Gardner-Roberson [G-R] class I or II) were treated with SRS from 2009 to 2023. This is a retrospective study. Survival analysis with Cox regression for hearing deterioration was performed.

Results

The median age was 55 years old. The median tumor volume was 0.089 cm³ and the median marginal dose was 12.0 Gy. Nonserviceable hearing deterioration occurred in 9 patients (24.3%), with a median onset of 11.9 months after SRS. The actuarial rates of serviceable hearing preservation were 86%, 82%, and 70% at 1, 2, and 3 years after SRS, respectively. A marginal dose >12 Gy, tumor volume >0.15 cm³, and baseline pure tone average >30 dB increased the risk of nonserviceable hearing deterioration with significant hazard ratios. There were 13 patients with petit VSs whose tumor volume was smaller than 0.05 cm³, and 11 of them were treated by a 4-mm single shot with a marginal dose of 12 Gy. None of the 13 patients had nonserviceable hearing deterioration.

Conclusions

Petit VSs that can be treated with 4-mm single or double shots with a marginal dose of 12 Gy may achieve hearing preservation after SRS. 

Objective Gamma knife radiosurgery(GKRS) has been recommended as a reasonable primary and adjuvant treatment modality for cavernous sinus hemangiomas(CaSHs). Single session radiosurgery may be contraindicated if tumors are adjacent to the optic pathways for the substantial risk of visual complication. This study was conducted to evaluate the efficacy and safety of dose-staged GKRS for perioptic CaSHs.

Methods From March 2018 to September 2020, 11 patients haboring CaSHs adjacent to the optic pathways received dose-staged GKRS treatment at Gamma Knife Center of Huashan Hospital. 10 patients were diagnosed according to clinical symptoms and classic MR images of CaSH, and only 1 patient had received transsphenoidal microsurgery before staged GKRS. There were 1 male and 10 female patients with a median age of 40 (range, 27~72) years old. The median tumor volume was 15.09 cm³ (range, 5.54~31.00 cm³). All of the enrolled patients underwent 2-dose-stage GKRS, and the median interval between the two GKRS treatments was 8 months (range 3~9 months). For the first stage GKRS procedure, the median isodose line was 45% (range 40%~50%), and the median marginal dose was 8.8 Gy (range 8~10 Gy). For the second GKRS treatment, the median isodose line was 46% (range 40%~52%), and the median marginal dose to the CaSHs was also 8.8 Gy (range 8~10 Gy).

Results The median follow-up duration was 40 months (range 25~60 months). The median tumor volume reduction was 64.2% (range, 20.3%~85.3%) at second-stage GKRS compared with the first-stage GKRS volume. At last follow-up, tumor control was achieved in all 11 patients and the median tumor shrinkage was 83.0% (range 70.6%~92.5%) compared to the pre-GKRS volume. Post-GKRS clinical improvement or stability was reported in 90.9% (n=10). No patient showed clinical deterioration. No radiation-induced optic neuropathy or neurological deficits were detected after staged GKRS.

Conclusions Dose-staged GKRS is an effective and safe alternative to either surgery or fractionated radiotherapy for perioptic CaSHs that are unsuitable for single session radiosurgery.

Single-session radiosurgery has to be suggested for patients with non-functioning adenomas who are not suitable for medical surgery or when a residual lesion is present. Multisession radiosurgery may be useful for larger adenomas or those located near the optic pathways. However, due to the absence of long-term tumor control data, the suitability of this treatment schedule has to be confirmed. The aim of this study is to examine the safety and efficacy of multisesion radiosurgery in this setting.

The present is an exploratory study, focusing on patients with residual/recurrent non-functioning pituitary adenomas who have been evaluated at our institution. Patients fulfilling the inclusion criteria (no prior cranial irradiation, absence of pregnancy, no contraindications for MRI or CT scans, and the ability to provide informed consent) are enrolled and treated with hypofractionated radiosurgery using CyberKnife technology (Accuray).

The primary end-point of the study is to assess early and delayed toxicity concerning cranial nerves and pituitary function post-treatment. Secondary end-points are late toxicities, local control, and evaluation of patients' quality of life (QoL).

From September 2020 to September 2023, 21 patients underwent multisession radiosurgery for pituitary adenomas. All patients received a total dose of 25 Gy delivered in 5 fractions over 5 consecutive days. At the time of treatment, the average age was 52 years (range 20-74 years, median 55 years).

The treated lesions had a mean volume of 10 cc (range 0.5-33 cc, median 6 cc). The mean value of the maximum point dose to the chiasm varied from 6 to 32 Gy. The mean value of the maxiumum and the mean doses to the pituitary gland, when identifiable, were 24 Gy (range 14-31 Gy) and 19 Gy (range 6-28 Gy), respectively.

Following a mean follow-up period of 32 months (range 6-36 months), 1 patient experienced transient dysphagia and dysphonia, which was successfully treated with low-dose oral dexamethasone, and 4 patients required minor adjustments in their substitutive hormonal therapy. Overall, visual function was generally maintained, and none of the treated tumors showed progression during the follow-up period.

While awaiting a more extended period of observation, the current study provides support for the safety of multisession radiosurgery and suggests its efficacy in the short term.

BACKGROUND: The purpose of intracranial arteriovenous malformations (AVMs) treatment is to prevent bleeding or subsequent hemorrhage with complete obliteration. For large, difficult-to-treat AVMs, multimodal approaches including surgery, endovascular embolization, and gamma knife radiosurgery (GKRS) are frequently used.

OBJECTIVE: To analyze the outcomes of AVMs treated with single-session, neoadjuvant, and adjuvant embolization GKRS. METHODS: We retrospectively reviewed a database of 453 patients with AVMs who underwent GKRS between January 2007 and December 2017 at our facility. The obliteration rate, incidence of latent period bleeding, cyst formation, and radiation-induced changes were compared among the 3 groups, neoadjuvant-embolized, adjuvant-embolized, nonembolized group. In addition, the variables predicting AVM obliteration and complications were investigated.

RESULTS: A total of 228 patients were enrolled in this study. The neoadjuvant-embolized, adjuvant-embolized, and nonembolized groups comprised 29 (12.7%), 19 (8.3%), and 180 (78.9%) patients, respectively. Significant differences were detected among the 3 groups in the history of previous hemorrhage and the presence of aneurysms (P < .0001). Multivariate Cox regression analyses revealed a significant inverse correlation between neoadjuvant embolization and obliteration occurring 36 months after GKRS (hazard ratio, 0.326; P = .006).

CONCLUSION: GKRS with either neoadjuvant or adjuvant embolization is a beneficial approach for the treatment of AVMs with highly complex angioarchitectures that are at risk for hemorrhage during the latency period. Embolization before GKRS may be a negative predictive factor for late-stage obliteration (>36 months). To confirm our conclusions, further studies involving a larger number of patients and continuous follow-up are necessary.

Background:

68Ga-DOTATATE PET-CT is useful in identifying somatostatin receptor (SSTR), which can help create a physiologic image of the extent of meningioma involvement and allow for a clearer determination of appropriate planning with observation, surgery or radiation therapy. 68Ga-DOTATATE PET-CT is able to detect and identify meningiomas with a sensitivity of 81% and specificity of 90%.  We have examined a series of fifteen cases in which this test was useful and affected the final patient treatment.  We have grouped these in to five indications to allow for further evaluation of this technology for treatment of meningiomas.

Methods:

Fifteen individual cases using 68Ga-DOTATATE PET-CT in meningiomas management were reviewed.  Upon reviewing these case studies, they were grouped into one of five categories. These categories were based the use and role 68Ga-DOTATATE PET-CT had on the meningiomas case. 

Results:

Meningioma management was affected by 1) Detection of new primary meningioma at a new anatomic Site, 2) Clarification of scar versus recurrence in a previously treated region. 3) Treatment planning for radiosurgery or surgical resection 4) Diagnoses of metastasis versus meningioma 5) Extent of disease demonstrating etiology of atypical facial pain. Seven of the fifteen cases used 68Ga-DOTATATE PET-CT to detect a new origin of meningioma not detected by MRI. The PET/CT scan directly allowed for management decision of gamma knife radiosurgery, proton therapy or re-resection of the second region. In Three cases, 68Ga-DOTATATE PET-CT was used to gain clarity of whether a site was a scar or a recurrence in the same location of prior therapy.  Two of these could be observed and the other one was appropriate for further treatment.  In three other cases, 68Ga-DOTATATE PET-CT was able to be used in planning treatment for either surgical or radiation therapy tumor volume.  For one unique case, we were able to use 68Ga-DOTATATE PET-CT in the diagnoses of metastasis versus meningioma, and allowed for detection of a meningioma instead of a breast cancer metastasis.  Another novel case allowed for 68Ga-DOTATATE PET-CT to delineate the extent of a meningioma extension into the infratemporal fossa as the cause of atypical facial pain.  

Conclusions:

68Ga-DOTATATE PET-CT in these fifteen cases identified five novel methods and uses in meningioma cases. The role of 68Ga-DOTATATE PET-CT is helpful in the multidisciplinary management of meningioma treatment.  

Introduction: Craniotomy is the gold standard treatment for meningiomas (MGMs) of medium size or larger, but there is often concern about postoperative deterioration of performance status (PS) in elderly patients. Stereotactic radiosurgery is considered as the next best option, but it is known that gamma knife radiosurgery (GKS) with single fraction has a poor local control rate for medium-sized MGMs with a tumor volume of more than 10 ml. The latest GKS systems allow fractionated radiotherapy with mask fixation, and appropriate radiosurgical techniques are now being explored for medium-sized or larger tumors. In this study, we retrospectively examined the preliminary results of hypofractionated GKS (fGKS) for medium-sized MGMs in elderly patients and discussed the significance of this strategy.

Methods: Five patients aged 75 years or older with neuroradiological diagnosis of MGM and tumor volume >10 ml who underwent fGKS were included. The age ranged from 75-89 (median 81) years, KPS 80-90 (median 80), tumor volume 10.5-18.0 (median 17.0) ml, and were localized in 2 cerebellopontine angle, 2 sphenoidal ridge, and 1 parasagittal. Three (60%) were symptomatic (visual impairment 2, dizziness 1). Each of these cases was treated with a prescription dose of 24-25 Gy/5 fractions.

Results: The follow-up period after fGKS ranged from 22-40 (median 30) months, and all patients were alive, with a tumor local control rate of 80% (4/5 patients). Tumor volume at the final neuroimaging evaluation was generally well reduced compared to at the time of fGKS, ranging from -66% to +49% (median -30%) in all but one case. In one case, the tumor grew after 6 months of fGKS and required craniotomy, and pathology showed a slightly elevated Ki-67 labeling index of 5-7%. Neurological symptoms in the three symptomatic patients improved in one, remained unchanged in two, and there were no adverse events associated with fGKS.

Conclusions: Although the results are preliminary, fGKS may be useful and safe for the maintenance of PS in elderly patients with medium-sized or larger MGMs. This suggests that fGKS may be a treatment option, especially in elderly patients with MGMs that are increasing in volume but who are hesitant to undergo craniotomy. Further experience with this strategy is needed in the future.