ESTRO 37 Abstract book

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ESTRO 37

Conclusion CyberKnife offers excellent local control of brain metastases in both the intact and post-operative setting. The initial Australian experience provides comparable local control rates compared to international series and at least comparable local control compared to other published Australian stereotactic series. EP-1215 Multi-fraction stereotactic radiosurgery for trigeminal schwannomas: experience treating 57 patients H.G. ZHU 1 , X. Wang 1 , E.M. Wang 1 1 Huashan hospital-Pudong-Fudan University, Neurosurgery & Cyberknife center, Shanghai, China Purpose or 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). Material and Methods A series of 57 TSs were treated using the CyberKnife from June 2007 to July 2015 with the multi-f raction SRS technique in our center. The mean age was 50 (range 21-78) years. Microsurgery preceded radiosurgery in 14 patients and Gammaknife SRS in 4 patients. The median tumor volume was 11.3 (range 2.1–48.9) cm³ and 33 of them were larger than 10.0 cm³. The prescription dose was 19.9 (range 13.2-24)Gy, which was delivered in 1-4 sessions. Results The follow-up period ranged from 27 to 112 months (median 61 months). In all patients MRI follow-up was obtained, the overall tumor control rate was 96.5%. The most frequent symptoms were hypoesthesia/ hyperesthesia in 33 patients, diplopia in 10 patients, facial pain in 8 patients. Neurological follow-up examination showed a stable status in 13 patients, whereas 31 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. Conclusion 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. EP-1216 Variation of the blood glucose during radiotherapy: an analysis among glioblastoma patients N.I. Oszfolk 1 , M.N. Duma 1 , K.J. Borm 1 , M. Mayinger 1 , T. Boeckh-Behrens 2 , M. Oechsner 1 , S.E. Combs 1 1 Klinikum rechts der Isar- TU München, Department of Radiation Oncology, München, Germany 2 Klinikum rechts der Isar- TU München, Department of Neuroradiology, München, Germany Purpose or Objective Many radiotherapy (RTx) patients with brain tumors undergo changes in their blood glucose (BG) during radiation. Several factors could be causing hyper- glycemia. The aim of this study was to assess the correlations between the radiation therapy dose to the central gustatory system (GS) and the BG values. Material and Methods 37 patients with regular BG measurements diagnosed with glioblastoma were investigated retrospectively. 59.5% were female and 40.5% male with a median age of 64.3 years (range 27.4 - 85.6). Diabetes (DM) history, BG

and CT fused images. Three different fractionations schedules were used: 10x4Gy, 5x6Gy, 5x7Gy according to PTV size or location. Patients were treated with IMRT or 3D planning. Daily ExacTrac image guided system with noninvasive frame-based mask and 6D coach was performed Results Median age was 57 years old. The most frequent primary tumor was lung (57%) followed by breast (26%). 84% of patients remained asymptomatic during treatment. With a median follow up of 15 months (1-53) 1 year disease free survival (DFS) was 90% and 2y DFS was 81%. Local control was achieved in 25 patients (84%). Relapse outside surgical bed occurred in 14 patients (46%) who were rescued with radiosurgery (10 p) or whole-brain radiation therapy (4 p) and 60% of these patients are alive with a median follow up of 12 months. One year overall survival was 70%. Conclusion Frameless image-guided LINAC-based adjuvant HFSRT after resection of brain metastasis is a therapeutical strategy that allows delay whole brain radiotherapy with an excellent local control and good tolerance. Further studies and longer follow up are necessary. EP-1214 Initial Australian experience utilising CyberKnife radiosurgery in the treatment of brain metastases J. Croker 1 , S. Bydder 2 1 Fiona Stanley Hospital, Department of Radiation Oncology, MURDOCH, Australia 2 Sir Charles Gairdner Hospital, Department of Radiation Oncology, NEDLANDS, Australia Purpose or Objective To compare the initial Australian results utilising the CyberKnife robotic radiosurgery system (CK) in treatment of brain metastases with national and international stereotactic data to assess efficacy. Material and Methods A retrospective analysis was performed utilising hospital records and a prospective (Radiosurgical Society) database. All patients who underwent radiotherapy for brain metastases, both in situ and post-operative, with CK at Sir Charles Gairdner Hospital, Nedlands, Western Australia, and who were followed-up for minimum 6 months (or until death) up to March 2017 were assessed. The primary endpoint for this study was local control. Other endpoints were distant brain failure and overall survival. Patient who died less than 90 days post-CK (i.e. did not have a post-CK surveillance MRI) were excluded from the local control analysis but included in the survival analysis. Results The cohort comprised 100 patients, 42 of which had had previous WBRT. Ninety patients had a single CK course, whilst 10 patients had multiple (salvage) courses. Non- small cell lung cancer (36%), Melanoma (24%) and breast cancer (19%) represented the majority of diagnoses. The median number of metastases treated in each course was 2 (range 1-18) with 35% solitary metastases and 53% being 2-5 metastases. Sixty-eight percent of cases treated de novo disease and 32% in the post-operative setting. Seventy-four percent of patients were treated with a single fraction (range 1-5 fractions). The median dose was 18 Gy (range 12.5 Gy- 30 Gy), prescribed to the 76- 82% isodose. Local control was achieved in 80% of assessable patients overall, and 86% of patient in the post-operative setting. Thirty-one percent of patients failed in the distant brain. For those that had intracranial relapse, the median time to local failure was 5.2 months and to distant failure was 5.0 months. The median overall survival was 10.25 months.