Tuesday 30 May
07:30

Tuesday 30 May

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BS4
07:30 - 08:30

BREAKFAST SEMINAR
Targeting Optimization

Moderators: Alessandra GORGULHO (Director of Research Affairs) (Sao Paulo, BRAZIL), Adrian MERLO (SWITZERLAND), Niklaus SCHAEFER (SWITZERLAND)
07:30 - 08:30 Multidisciplinary imaging in targeting optimization for skull base meningiomas. Antonio NICOLATO (Neuroradiosurgeon) (Verona, ITALY)
07:30 - 08:30 Principle of Selective Interstitial radiation therapy. Niklaus SCHAEFER (SWITZERLAND)
07:30 - 08:30 Targeted alpha therapy for malignant gliomas WHO II-IV. Adrian MERLO (SWITZERLAND)
Parallel 1- Prince

Tuesday 30 May

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BS5
07:30 - 08:30

BREAKFAST SEMINAR
Motion Management Techniques for SBRT of Lung & Liver

Coordinator: Fang-Fang YIN (Medical Physicist/Professor) (Durham, NC, USA)
Moderators: Jeffrey D BRADLEY (St Louis, USA), Samuel RYU (Professor) (Stony Brookn NY, USA)
07:30 - 08:30 Speaker 1: Techniques and processes for Motion Management Techniques of Lung & Liver. Fang-Fang YIN (Medical Physicist/Professor) (Durham, NC, USA)
07:30 - 08:30 Speaker 2: Motion considerations for lung SBRT. Jeffrey D BRADLEY (St Louis, USA)
07:30 - 08:30 Speaker 3. Jackie WU (Professor) (Durham, USA)
Parallel 2- Queen

Tuesday 30 May

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BS6
07:30 - 08:30

BREAKFAST SEMINAR
Standardization

Coordinator: Caroline CHUNG (Associate Professor, Radiation Oncology) (Houston, USA)
Moderators: Evelyn HERRMANN (Radiation Oncology) (Bern, SWITZERLAND), Dheerendra PRASAD (Professor and Medical Director) (Buffalo, USA)
07:30 - 08:30 Standardization: essential steps towards quality, collaboration and cutting edge progress. Caroline CHUNG (Associate Professor, Radiation Oncology) (Houston, USA)
07:30 - 08:30 Geometrical accuracy and quality assurance of MRI protocols for gammaknife treatments. Uulke VAN DE HEIDE (THE NETHERLANDS)
07:30 - 08:30 Global assessment of current practices & vision for convergence. Dheerendra PRASAD (Professor and Medical Director) (Buffalo, USA)
Parallel 3- BB King
08:45

Tuesday 30 May

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PS2
08:45 - 10:00

PLENARY SESSION 2

Moderators: Adrien COSINSCHI (Radiation Oncologist) (Vevey, SWITZERLAND), Bruce POLLOCK (Physician) (Rochester, USA), Pierre-Hugues ROCHE (Marseille, FRANCE)
08:45 - 08:55 Data Blitz: Updates on Functional Radiosurgery. Romain CARRON (MEDECIN) (MARSEILLE, FRANCE)
08:55 - 09:05 Special Lecture: Introduction to Diffusion MR image processing. Jean-Philippe THIRAN (Director) (Lausanne, SWITZERLAND)
09:05 - 09:15 Minimal requirements for safe Frameless Radiosurgery. Johan CUIJPERS (Head of Physics) (Amsterdam, THE NETHERLANDS)
09:15 - 09:25 Pros & Cons - Progression versus pseudoprogression: Is stability of Vestibular Schwannoma before SRS a major predictor of tumor control? Yes. Bruce POLLOCK (Physician) (Rochester, USA)
09:25 - 09:35 Pros & Cons - Progression versus pseudoprogression: Is stability of Vestibular Schwannoma before SRS a major predictor of tumor control? No. Philip THEODOSOPOULOS (Neurosurgeon) (San Francisco, USA)
09:35 - 09:45 Pros & Cons - Very big Vestibular Schwannomas: Is limited better than extended resection in combined approaches? Yes. Roy Thomas DANIEL (Médecin Cadre) (Lausanne, SWITZERLAND)
09:45 - 09:55 Pros & Cons - Very big Vestibular Schwannomas: Is limited better than extended resection in combined approaches? No. Pierre-Hugues ROCHE (Marseille, FRANCE)
Stravinski Auditorium
10:00

Tuesday 30 May

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break10
10:00 - 10:30

Coffee Break

10:30

Tuesday 30 May

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PS3
10:30 - 11:30

PLENARY SESSION 3

Moderators: Roy Thomas DANIEL (Médecin Cadre) (Lausanne, SWITZERLAND), Yoshiaysu IWAI (Neurosurgery, Radiosurgery) (Osaka, JAPAN), Antonio NICOLATO (Neuroradiosurgeon) (Verona, ITALY), Karl SCHALLER (Genève, SWITZERLAND)
10:30 - 10:40 Recent developments in Proton Therapy Technology: a critical thinking approach. David WIKLER (BELGIUM)
10:40 - 10:50 Pros & Cons - Who has the bragg'ing rights: Are Protons superior to Stereotactic Photons in Chordomas and Chondrosarcomas? Yes. Damien WEBER (Villigen, SWITZERLAND)
10:50 - 11:00 Pros & Cons - Who has the bragg'ing rights: Are Protons superior to Stereotactic Photons in Chordomas and Chondrosarcomas? No. Dheerendra PRASAD (Professor and Medical Director) (Buffalo, USA)
11:00 - 11:10 Limits of resection in skull-base tumors. Paul GARDNER (Pittsburg, USA)
11:10 - 11:25 Proton-beam irradiation of ocular tumors. Leonidas ZOGRAFOS (SWITZERLAND)
Stravinski Auditorium
11:30

Tuesday 30 May

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OSP15
11:30 - 12:30

Parallel Session - SRS versus Alternative Focal Approaches

Moderators: Javier FANDINO (SWITZERLAND), Adrian MERLO (SWITZERLAND), Jason SHEEHAN (Charlottesville, USA)
11:30 - 11:45 HIFU in tremor. Howard EISENBERG (USA)
11:45 - 12:00 HIFU for brain tumors. Daniel COLUCCIA (SWITZERLAND)
12:00 - 12:15 Tumor Treating Fields in neuro-oncology. Andreas HOTTINGER (Lausanne, SWITZERLAND)
12:10 - 12:30 Focal therapies in prostate tumors. Massimo VALERIO (Lausanne, SWITZERLAND)
Stravinski Auditorium

Tuesday 30 May

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OSP14
11:30 - 12:30

Parallel Session - Imaging

Moderators: Antonio DE SALLES (Professor - Chief) (Sao Paulo, BRAZIL), Thomas MINDERMANN (Neurosurgeon) (Zürich, SWITZERLAND)
11:30 - 11:40 #8971 - 11C-Methionine PET for distinguishing recurrent brain metastases from radiation necrosis: Limitations of diagnostic accuracy and long-term results of salvage treatment.
11C-Methionine PET for distinguishing recurrent brain metastases from radiation necrosis: Limitations of diagnostic accuracy and long-term results of salvage treatment.

Background: Imaging features of radiation necrosis (RN) are similar to those of local recurrence (LR) of brain metastases (BM) on conventional diagnostic imaging technique. 11C-Methionine PET (MET-PET) has reportedly been useful to provide a differential diagnosis between LR and RN. The aim of this study was to investigate the diagnostic performance of MET-PET and the mid- to long-term results of subsequent management.

 

Methods: The eligible subjects were enlarging contrast-enhanced lesions (>1cm) on MR imaging after any kind of radiotherapy for BM, suggesting LR or RN but difficult to differentiate. From August 2013 to September 2016, MET-PET was performed for 35 lesions in 30 patients (median age: 63 yrs). Tracer accumulation in the regions of interest was analyzed as standardized uptake value (SUVmax) and lesion/normal tissue SUVmax ratios (LNR) were calculated. The cut-off value of LNR was provisionally set at 1.40. Salvage treatment strategies determined based on MET-PET diagnosis and treatment results were investigated. The diagnostic accuracy of MET-PET was analyzed by Receiver operating characteristic (ROC) curve analysis.

Results: Median interval from primary radiotherapy to MET-PET was 21 months and 13 lesions had received radiotherapy twice or more. The MET-PET diagnoses were LR 17 and RN in 18 lesions. In the median follow-up time of 15 months, final diagnoses were confirmed in 31 lesions (Histological 16, Clinical 15). Mean LNR of LR and RN were 1.70 ± 0.31, 1.13 ± 0.25, respectively. Sensitivity, Specificity, positive predictive value and negative predictive value were 80%, 88%, 86%, 82%, respectively. ROC curve analysis indicated the optimal LNR cut-off value as 1.39 (AUC: 0.89). LNR of 5 lesions incorrectly diagnosed by MET-PET were ranged within 1.4 ± 0.2. Salvage treatment for 17 lesions predicted as LR were surgical resection in 7, radiosurgery in 8. Of 18 lesions predicted as RN, 6 were surgically treated and 3 needed repeat bevacizumab treatment. In 4 lesions which failed to obtain diagnostic conclusion, salvage treatment based on MET-PET diagnosis did not provide significant improvement and treatment strategies had to be changed.

Conclusions: 11C-Methionine PET appeared to have a reliable diagnostic performance for distinguishing LR from RN. The provisional LNR cut-off value of 1.4 in our institution was found to be relevant. Limitations of diagnostic accuracy should be recognized in cases with LNR close to the cut-off value.

Shoji YOMO (Tokyo, JAPAN)
11:40 - 11:50 #9983 - Differentiating post-SRS radionecrosis from tumor progression using MRI Arterial Spin-Flow Labelling (ASL): Quick, colorimetric, quantifiable and necessary baseline blood flow data used to evaluate SRS treatment of brain metastases and predict outcomes.
Differentiating post-SRS radionecrosis from tumor progression using MRI Arterial Spin-Flow Labelling (ASL): Quick, colorimetric, quantifiable and necessary baseline blood flow data used to evaluate SRS treatment of brain metastases and predict outcomes.

The radiographic differentiation of post-SRS radiation change versus tumor progression is a major issue for any SRS center. We have been using non-Gd+ ASL as a reliable pulse sequence to help decide on the dominant tissue in these lesions and have used this data to assist in the decision for further treatment for four years now. Recent published data confirms that post-SRS elevated flow can be a very reliable predictor of recurrent tumor but the largest study failed to establish baseline data, and we have found that up to 40% of pre-treatment brain metastasis do not have elevated flow at baseline, therefore these tumors would not be expected to have elevated flow when they re-occur. If a baseline is not established, then these ‘low flow’ metastasis would be mistaken as radiation change upon follow-up. We have contacted multiple international centers to join in a larger data pool to verify our initial findings and establish an optimal statistical data base and promote this two-minute pulse sequence characterization to be used with confidence.

Elisheva LAMBERT (Tel Aviv, ISRAEL), Dr. Stephen HOLMES
11:50 - 12:00 #10001 - Integration of MR Guided Linear Accelerator for Treatment of Multiple Brain Metastases with Single-Isocenter using Stereotactic Radiosurgery.
Integration of MR Guided Linear Accelerator for Treatment of Multiple Brain Metastases with Single-Isocenter using Stereotactic Radiosurgery.

Objectives

The purpose of study was to investigate the treatment planning capabilities for multiple brain metastases using stereotactic radiosurgery with a shared isocenter on an integrated 0.35T magnetic resonance imaging guided Linear Accelerator (MR-Linac) platform.

 

Methods

The MR-Linac consists a 0.35T double donut superconducting MRI and a ring-gantry mounted Linac system.  The Linac has a 6X flattening filter free (FFF) beam with a dose rate up to 600 MU/min. The multileaf collimator (MLC) has a novel double-stack design to achieve a 4 mm spatial resolution which is half of the leaf width. The treatment planning process for two patients with 3 brain metastatic lesions and one patient with 2 lesions were studied. Single-isocenter IMRT plans with 10-15 beams were used to generate treatment plans for multiple metastases in a coplanar setting. The isocenter was placed around the geometric center among the lesions. All plans were calculated with 1 mm dose grid resolution using a fast Monte Carlo algorithm with a prescription dose of 18 Gy for each lesion.  The IMRT optimization employed the same Monte Carlo algorithm for calculating the dose distribution at each iteration step.  2.4 millions histories were simulated to achieve a statistical uncertainty of 2%, on average, at Dmax.

Plan quality was evaluated using the conformity index (CI), homogeneity index (HI) and gradient index (GI). The volume of normal brain that received 4, 8, and 12 Gy (V4, V8, and V12, respectively), as well as the mean dose were used to evaluate the dose to the normal brain. The total MUs, segments, and beam on time, were also recorded.

 

Results

The average planning target volume was 0.34 cm3 (range 0.06-0.74 cm3). The CI, HI and GI of each plan were 1.31/1.23/5.93, 1.61/5.98/5.27, and 1.31/1.23/5.27 respectively.  V4Gy, V8Gy, V12Gy of normal brain of each plan were 1.02/0.34/0.14, 3.32/0.58/0.22, 1.27/0.20/0.02 %. The mean dose of normal brain tissue for all three patients were 0.37, 0.78 and 0.60 Gy. The total MU of each plan was 5510, 7488, and 6547 and the corresponding beam on time was 9, 12, and 11 minutes.  Monte Carlo based dose calculation required less than 5 minutes.

 

Conclusions

A novel double-stacked MLC design was able to achieve a finer leaf width, which provided better dose conformity to target lesions under 1.0 cm3. This preliminary investigation demonstrated that excellent plan quality was achievable on the MR-Linac to treat multiple brain metastases with a single isocenter.

Ning WEN (Detroit, USA), Anthony DOEMER, Carri GLIDE-HURST, James VICTORIA, Iwan KAWRAKOW, Qixue WU, Liu CHANG, Farzan SIDDIQUI, M. Salim SIDDIQUI, Indrin CHETTY, Benjamin MOVSAS
12:00 - 12:10 #10256 - Radiomics analysis for assessing concurrent stereotactic radiosurgery and bevacizumab treatment of recurrent malignant gliomas.
Radiomics analysis for assessing concurrent stereotactic radiosurgery and bevacizumab treatment of recurrent malignant gliomas.

This study explored the use of radiomics features as potential biomarkers for predicting the outcome of recurrent malignant gliomas (MG) patients treated by concurrent stereotactic radiosurgery (SRS) and Bevacizumab (BVZ). Thirteen patients with recurrent MG were retrospectively studied. Lesions with <3 cm in diameter were treated in a single fraction and 3-5 cm in diameter were treated in 5 fractions. BVZ was administered immediately before SRS and 2 wks later. MRI studies, including T1- and T2-weighted, dynamic contrast-enhanced (DCE) and diffusion weighted (DW), were performed before SRS, 1 week and 2 months after the completion of SRS. Functional paremeters including apparent diffusion coefficient ADC, micro-vascular transfer constant Ktrans, brain blood flow FB, and blood volume vB were analyzed. Radiomics analysis extracts imaging features (a total of 252 radiomics features) and correlates features with outcomes. Statistical tests were performed with Bonferroni correction to evaluate the change of functional parameters and texture features 1 week and 2 months after SRS. The changes between different WHO grades were evaluated. Correlation tests were used to examine the relationships between changes of functional parameters/radiomics features and patient survival time after SRS. Selected features were used to predict the patient survival time after treatment using Support Vector Regression (SVR) with leave one out cross validation (LOOCV). The median survival time was 13.7 months after treatment. Radiomics analysis was also performed in normal tissues receiving 12 Gy or above. DCE results showed that GTV blood flow dynamics parameters Ktrans(p=0.02) and vB(p=0.04) significantly decreased at 2 months after SRS. No functional parameters reflected statistically significant treatment response at 1 week after SRS. 20 radiomics features from anatomical T1w gray level images and 25 features from functional parameters maps (Ktrans:18, ADC:7) showed significant changes 2 months after SRS. Among these features, 7 Ktrans features and 3 ADC features reflected significant difference as early as 1 week after SRS between WHO Grade 3/4 patient groups. The changes of 16 radiomics features (Ktrans:11, FB:5) at 2 months after SRS were significantly correlated with patient survival time. Using 2 selected signature features from T1w scans and 3 from DCE parametric maps, 9 out of 13 patients’ survival time could be accurately predicted. The preliminary results demonstrate the effectiveness of using radiomics features for predicting early treatment response. The results also suggest the potential application of radiomics features as potential biomarkers for individualized treatment regime optimization.

Fang-Fang YIN (Durham, NC, USA), Chunhao WANG, Wenzhen SUN, Zheng CHANG, John KIRKPATRICK
12:10 - 12:20 #10411 - Tractography in gamma knife anterior capsulotomy planning.
Tractography in gamma knife anterior capsulotomy planning.

Objective: The role of tractography in Gamma Knife Capsulotomy (Gamma-C) planning is still unclear. The anterior internal capsule (AIC) tractography could demonstrate the most important fibers necessary to be severed to achieve best results and reduce complications.

 

Methods: In this study, the AIC of 20 patients undergoing functional neurosurgery for diverse diagnosis was defined bilaterally in the Iplannet Stereotaxy Software (Brainlab, Germany). The 40 AIC tractography were divided in two halves based on coronal views. The direction of the fibers was studied in the two segments with the objective to define which portions of the fibers would be reached by a single isocenter placed in the ventral most portion of the AIC, and which fibers would be reached if added a second isocenter to obtain an oval shaped distribution in the direction of the ventral-dorsal portion of the AIC. The isocenters were adjusted based on Gamma Plan® Treatment Planning System - TPS (Elekta, Sweden).

 

Results: Significant difference was observed between both plans, with the single isocenter reaching substantially fibers directed to the ventral-mesial-orbitofrontal fibers, while the two isocenters plan achieved also fibers directed to the lateral-frontal cortex. Classical capsulotomy suggests that these lateral fibers should be also reached, based on size of the lesion, oval in shape.

 

Conclusions: The routine use of DTI tractography of the AIC may be important to the planning of Gamma Knife capsulotomy. DTI tractography, as well as anisotropy showing the capsule promises the have important role in Gamma-C. In the case of Gamma-C it allows for objective definition of dose constrains to the internal capsule and the fibers to be reached. It may direct the procedure based on severity of the disease, as well as its dominant symptomatology.

Antonio DE SALLES, Alessandra GORGULHO, Joao Gabriel GOMES (Sao Paulo, BRAZIL), Anderson PASSARO
12:20 - 12:30 #10430 - Stereotactic diffusion tensor imaging tractography for gamma knife stereotactic radio-surgery - Evolution of technique & application.
Stereotactic diffusion tensor imaging tractography for gamma knife stereotactic radio-surgery - Evolution of technique & application.

Integration of modern neuroimaging into treatment planning has increased the therapeutic potential and safety of stereotactic radiosurgery. We previously reported our method of integrating stereotactic diffusion tensor imaging (DTI) tractography into conventional treatment planning for Gamma Knife radiosurgery (GKRS). The aim of this study is to address  some of the technical limitations of our previously reported techniques in a larger series

Methods: Seventy patients who underwent GKRS composed the study cohort. 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. All studies were performed using a 1.5-T magnet with a single-channel head coil. DTI was performed with diffusion gradients in 32 directions and coregistered with the volumetric T1-weighted study. DTI postprocessing by means of commercially available software allowed tensor computation and the creation of directionally encoded color, apparent diffusion coefficient & fractional anisotropy mapped sequences. In addition, the software allowed visualized critical tracts to be exported as a structural volume and integrated into GammaPlan as an “organ at risk” during shot planning. Combined images were transferred to GammaPlan and integrated into treatment planning.

Results: Stereotactic DTI images were successfully acquired in all patients, with generation of correct directionally encoded color images. Tract generation was straightforward and reproducible, particularly for axial tracts such as the optic radiation and the arcuate fasciculus. In our original dtudy we noted that Corticospinal tract visualization was hampered by artifacts from the base of the stereotactic frame, but this was overcome by adjusting the gradient parameters. Coregistration of the DTI series with the T1-MR treatment volume at imaging is essential for the generation of correct tensor data. Most patients had pathology in the vicinity of eloquent tracts and/or the cortex. One patient with mesial temporal AVM developed delayed worsening of a pre-existing hemianopia. no other neurological deficits due to radiation were recorded at follow-up.

Conclusions: Reports in the medical literature have suggested that white matter tracts (particularly the optic radiation and arcuate fasciculus) are more vulnerable to radiation during SRS than previously thought. Integration of stereotactic tractography into GK-SRS 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

Cormac GAVIN (London, UK), H. Ian SABIN
Parallel 1- Prince

Tuesday 30 May

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OSP13
11:30 - 12:30

Parallel Session - WFSBS: Hypofractionation in skull-base

Moderators: Patrick HANSSENS (Radiation Oncologist) (Tilburg, THE NETHERLANDS), Oscar MATZINGER (Vevey, SWITZERLAND), Piero PICOZZI (Director) (MILANO, ITALY)
11:30 - 11:40 #9896 - Predictors of local control and comparison of single versus fractionated stereotactic radiotherapy for meningiomas – A Single institutional experience.
Predictors of local control and comparison of single versus fractionated stereotactic radiotherapy for meningiomas – A Single institutional experience.

OBJECTIVES  : To assess the predictors for local control and to compare  outcomes of  Linac  based SRS(stereotactic radiosurgery) with  FSRT(fractionated stereotactic radiotherapy) for meningiomas

 

METHODS AND MATERIALS : 45 patients of meningioma treated using LINAC based SRS and FSRT were retrospectively analyzed in our institute  diagnosed( radiological diagnosis =30, and biopsy proven =15) between 2007 to 2016. Male to female ratio was 17: 28 .12 patients were treated radically with SRS  and 33 patients (20 were radically treated, 8 received adjuvant radiation and 5 had radiation on recurrence, post surgery) were treated with FSRT. Patients who received re-irradiation were not included in the study. The median age group in SRS arm was 50 years ( range 32 -72 years)and in FSRT arm  55 years(30- 76 years) The median dose for SRS  was 15Gy (range 12-16Gy), and for FRST it was 25Gy (range 25-30Gy).The median PTV volume in SRS arm was 3.25cc ( range 0.75 to 10.5cc), and in FSRT arm 13.25cc  (range 10.45 to 65.3cc). The patients were followed by clinical examination as well as serial imaging with MRI (Magnetic resonance imaging).

 

RESULTS : The median follow up of the entire cohort was 54 months( range 6 – 84months).The median follow up of SRS arm and FSRT  arm was 48 months(range 12- 72months) and 72 months( range 6- 84months)  respectively . The overall survival was 100% in both the groups.  The 5 year local control was equivalent in both SRS and FSRT arm (91.6 vs 90.2%)(p =0.512). On univariate analysis  of the whole cohort, we found that age ,gender and PTV volume were predictors for local control. Local control was better for age group < 60 years ( p = 0.043). Females had longer time to relapse than males (p =0.026).The 5 year Local control was 100% for a tumor volume of ≤ 15cc and 91.1% for  a tumor volume of  >15cc (p= 0.044). No radiation late damage or any adverse events were observed during follow up period in both the arms.

 

CONCLUSION  : SRS and FSRT are equally effective  in terms of local control and complication rates. SRS is better for smaller volumes. FSRT is suitable for larger volumes,and with or without surgery .Age, gender and PTV volumes are important predictors for tumor control. Proper selection of cases and longer follow up is required for best outcomes.

Sanjay HUNUGUNDMATH (pune, INDIA), Sumit BASU, Bhooshan ZADE, Rahul SHARMA, Ashok BHANAGE, Sathiyanarayanan VATYAM
11:40 - 11:50 #9932 - Multi-fraction stereotactic radiosurgery for trigeminal schwannomas: a retrospective study of 56 patients.
Multi-fraction stereotactic radiosurgery for trigeminal schwannomas: a retrospective study of 56 patients.

Objective: Trigeminal schwannomas (TSs) have traditionally been treated by surgery. This retrospective study illustrates the outcomes of a series of TSs, most of which are large tumors, after multi-fraction stereotactic radiosurgery (MF-SRS).

Methods: A series of 56 TSs were treated using the CyberKnife from June 2007 to June 2015 with the multi-fraction SRS technique in Huashan Hospital, Shanghai, China. The mean age was 50 (range 21-78) years. Microsurgery preceded radiosurgery in 13 patients and Gammaknife SRS in 4 patients. The median tumor volume was 13.3 (range 2.1–48.9) cm³ and 32 of them were larger than 10.0 cm³. The prescription dose was 19.8 (range 13.2-24)Gy, which was delivered in 1-4 sessions.

Result: The follow-up period ranged from 19 to 103 months (median 53.5 months). In all patients MRI follow-up was obtained, the overall tumor control rate was 96.4%. The most frequent symptoms
were hypoesthesia/hyperesthesia in 32 patients, diplopia in 10 patients, facial pain in 8 patients. Neurological follow-up examination showed a stable status in 13 patients, whereas 30 patients noted improvement of at least one of their presenting symptoms after treatment. One patient noted a transient ptosis the next day after the first fraction and recovered in a week. One patients had a symptomatic cyst formation of tumor 6 months after SRS, followed by a second subtotal resection. One patient recieved a VP shunt 8 months after SRS which was due to hydrocephalus.

Conclusions: Cyberknife multi-fraction SRS is an effective and minimally invasive management option for patients with residual or newly diagnosed trigeminal schwannomas with respect to not only long-term local tumor control but also neuro-functional preservation.

Hua Guang ZHU (Shanghai, CHINA), Enmin WANG, Xin WANG
11:50 - 12:00 #9970 - Results of 5-fraction hypofractionated gamma Knife radiosurgery for benign neoplasms close to optic pathways.
Results of 5-fraction hypofractionated gamma Knife radiosurgery for benign neoplasms close to optic pathways.

Introduction:

We evaluate the clinical and radiological outcome of a series of 14 patients treated for a benign tumor using hypofractionation with the Gamma Knife.

Materiel & Methods:

All 14 patients of our series had a benign tumor located close to the optic pathways. There were 11 meningioma, 2 pituitary adenomas and 1 craniopharyngioma. All patients were treated with 5 daily fractions of a 5-Gy margin dose, either with a frameless system Extend (n=9) or with a conventional frame (n=5) repositioned each day.  For frameless procedures, the Extend system was used and provided a submillimetric precision of positioning for all sessions of irradiation.

Results:

All patients were followed prospectively. The median follow-up duration was 3.75 years (range 2.5 - 5.5 y). The visual status remained stable for 13 patients and improved for 1 patient. The tumor volume remained stable for 3 patients, reduced over time for 10 patients, and increased for 1 patient. This patient developed an extension of his initial tumor that necessitates a new radiosurgical irradiation on the cavernous sinus. One patient developed 2 new meningiomas 2.5 years after irradiation in other locations, which could have been radiation-induced. No other morbidity was seen.

Conclusions:

The medium- to long-term clinico-radiological outcomes of this series of 14 patients treated for a benign tumor using 5 fractions with the Gamma Knife showed excellent results with a high rate of tumor control and no worsening of the visual status.

 

Daniel DEVRIENDT (Brussels, BELGIUM), Cecile RENIER, Nicolas MASSAGER
12:00 - 12:10 #10066 - Five fraction Stereotactic Radiosurgery (SRS) for Brain meningiomas.
Five fraction Stereotactic Radiosurgery (SRS) for Brain meningiomas.

Objectives: To describe the efficacy and toxicity of the five fraction stereotactic radiosurgery ( SRS) for brain meningiomas.
 
Background: Effectiveness of conventional adjuvant EBRT, affront single session gamma knife radiosurgery and moderately hypo fractionated radiotherapy for brain meningiomas are wel studied and proven to have good local controls with minimum side effects.

Five fractions hypo-fractionated radiotherapy (multisession SRS) was used for relatively large tumors and for those closely lying with critical organs and not suitable for gamma knife single session radiosurgery. This schedule was considered to be beneficial equivalent to single session in terms of local control rate while good protection of critical organs in terms of fractionated irradiation for the large volume meningiomas. 
 
Methods: From 01.01.10 to 30.06.16, 1220 patients were treated on Synergy-S (Linac based radiosurgery system). 100 patients of intracranial meningiomas (including recurrent) were treated with 5 fractions radiosurgery. 40% were male and 60% were female patients. Mean age was 41.74 years (range: 18-67 years). Patients were followed up at 6 weeks, 3 months and then 6 months till 5 years time. Mean volume (PTV) was 46.87 cc (range: 2.20-90.20cc).Prescription dose 2500 cGy was used in five fractions at 400 to 500 cGy/day( Mean Fraction dose= 4.5 Gy/day) . Mean prescription Isodose line was 80 %(range: 65-100%). Median Maximum Dose was 3119 cGy(range: 2442- 4284 cGy). Median Mean dose was 3070 cGy (range: 2251-3592 cGy). Median Minimum dose was 2321cGy(range:1909-2950 cGy).  Review of literature by using Pubmed, Medscape and Pubmed Central was carried out to establish the safety and efficacy of 5 fractions SRS in brain meningiomas. 

Results: Clinical Improvement was seen in about 88 % of the patients, radiologically most of the tumors were stable around 68 %, 10 % had small residual disease while 10% progressed from original size at about 18 months after SRS. 02% patients were lost to follow-up. 10% patients were dead at median follow-up time of 4.2 years (range:1-5.5 years). 50 % of the dead patients had non tumor related death, while 50% had death due to progressive disease. No acute toxicity was observed, while use of steroids was prolonged in about 10 % of the patients mean duration was 3 months (range 1-6 months).

Conclusion: This retrospective study revealed high local tumor control rate and acceptable toxicity of five fractions radiosurgery for brain meningiomas. Further larger  studies required to establish its future use.

Azhar RASHID (KARACHI, PAKISTAN), Muhammad Ali MEMON, A Sattar M HASHIM, Muhammad Abid SALEEM
12:10 - 12:20 #10375 - Staged radiosurgery for large/critical intracranial meningiomas: a monocentric prospective study.
Staged radiosurgery for large/critical intracranial meningiomas: a monocentric prospective study.

Background.The treatment of choice for intracranial meningiomas is surgical removal. However, the complete resection of meningiomas can be difficult or impossible, because of their extension, their proximity to cranial nerves, vascular structures or eloquent areas. Meanwhile, single and staged radiosurgery, in exclusive, adjuvant or salvage setting represents an alternative or complementary viable treatment to the neurosurgery.

Under these circumstances, the staged radiosurgery treatments have been increasing and several authors published excellent results after staged-SRS with a local control (LC) ranging between 90% and 100% and a low treatment-related toxicity, above all because of the potential to deliver sharply focused high doses per fraction without increasing the risk of toxicity.

We present the early and medium-term results of first 53 patients of our ongoing prospective trial on staged radiosurgery for large and/or critical intracranial meningiomas. Reports of symptom control and neurological status are also evaluated.

Methods. The eligibility criteria were either histologically confirmed or imaging-defined benign meningioma diagnosis; large or medium lesion size and/or in critical area; signed informed consent; age ≥ 18 years; and Karnofsky Performance Status (KPS) ≥ 70. All enrolled patients were prospectively followed with clinical, neurological and radiological examinations. The follow-up evaluations were performed after 4 months from the staged-SRS, afterwards every 6 months during the first 2 years and then annually.

Results.The median follow-up for the entire series was 38 months (range, 4-52 months). The LC was obtained in 46 patients (98%) out of 47 available for MRI volumetric analysis. Nineteen (40%) patients presented a partial response, 27 patients (58%) a stable disease. Among 31 (66%) patients who were symptomatic before s-SRS, neurological follow-up showed an improvement in 15 patients (48.3%), stable clinical course in 12 patients (38.7%) and a persistent deterioration of clinical symptoms in 4 patients (13%). The acute toxicity was registered in 8 patients (23.5%). These new symptoms turned up in the patients within few weeks. The adverse events not correlated with radiotherapy were registered in 4 patients (8.5%).  None late symptoms due to staged-SRS were reported.

Conclusion.Our findings show that staged-SRS using the CyberKnife is a safe and effective option in the treatment of large-volume benign meningiomas. A good tumour control and a low morbidity and toxicity rates were achieved in our series, either as a primary or adjuvant approach. Long-term follow-up is warranted to confirm these results.

Valentina PINZI (Milan, ITALY), Alberto BOSETTI, Marcello MARCHETTI, Francesco GHIELMETTI, Milda CERNIAUSKAITE, Laura FARISELLI
12:20 - 12:30 #10389 - Tumor volume reduction and functional outcomes in radiosurgery and fractionated radiotherapy for cavernous sinus meningiomas.
Tumor volume reduction and functional outcomes in radiosurgery and fractionated radiotherapy for cavernous sinus meningiomas.

Introduction

Radiosurgery (RS) and fractionated radiotherapy (FRT) are part of the therapeutic armamentarium for the management of cavernous sinus meningiomas. We propose a systematic review of the local tumor control and clinical outcomes after monofractionated treatment, including gamma knife (GKRS) and linear accelerator (LinacRS), or fractionated radiotherapy.

Materials and Methods

We performed a search in PubMed based on the following Mesh terms: “cavernous sinus”, “meningioma”, “radiosurgery”, “gamma knife”, “linac”, “cyberknife”, and “radiotherapy”. Among 425 screened studies, 36 matched all selection criteria: 24 for GK, 5 for Linac and 7 for FRT.

 

Results

Were included 2817 patients (GKRS=2047, LinacRS=350, FRT=420). Half of patients benefited from upfront RS or FRT; the other half benefited from adjuvant RS or FRT (combined approach or tumor recurrence).  Mean target volume was smaller for RS as compared to FRT (p=0.07). Median marginal dose was 13.9 Gy (range, 11 to 28) for GKRS and 14 Gy (range, 12.8 to 17.7) for LinacRS. For FRT, patients received a mean dose of 51.2 Gy (25.5 fractions, 1.85 Gy each). Mean follow-up was: 48 months (range, 15 to 89) for GKRS, 69 months (range, 46 to 87) for Linac and 59.5 months (range, 33 to 83) for FRT. PFS at 5 years for GKRS, LinacRS and FRT were respectively: 93.6%, 95.6% and 97.4% (p=0.32, Kruskal-Wallis). Monofractionated treatments (GKRS and LinacRS) induced more tumor volume regression than FRT (p=0.001). Tumor recurrence or progression ranged between 3 and 5.8%, without statistically significant difference between modalities (p>0.05). Trigeminal symptoms improved in approximately 54%, and III-IV-VI CN palsies improved in approximately 45%. After GKRS, visual acuity improved in 21% (not enough data available for other modalities). De novo deficits occurred in 5 to 7.5% and adverse radiation effects in 4.6 to 9.3% (all techniques pooled).

Conclusion

RS achieved a twice-higher rate of tumor volume regression than FRT. GK series reported an improvement in visual acuity in 21% of the cases. GK, Linac and FRT provided similar clinical post therapeutic outcomes for the trigeminal and oculomotor CN. 

Henri-Arthur LEROY (Lille), Constantin TULEASCA, Nicolas REYNS, Marc LEVIVIER
Parallel 2- Queen
12:30

Tuesday 30 May

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12:30 - 14:00

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