ESTRO 36 Abstract Book

S612 ESTRO 36 2017 _______________________________________________________________________________________________

2 UF Health Cancer Center-Orlando Health, Radiation Oncology, Orlando, USA Purpose or Objective We examined the impact of patient and tumor-specific factors on overall survival in patients with brain metastases from non-small cell lung cancer (NSCLC) treated with stereotactic radiosurgery (SRS). Material and Methods We undertook an institutional review board-approved retrospective analysis of patients treated with LINAC- based SRS for brain metastases from non-small cell lung cancer between November 2008 and July 2016 at our institution. We identified 418 metastatic brain lesions treated in 136 non-small cell lung cancer (NSCLC) patients. Out of the 418 treated brain metastases, 376 had at least one follow up study. Patients were followed with serial brain MRIs with contrast to assess for local progression and recurrence every 2-3 months. Patient characteristics collected included: extracranial disease (ECD) status, Karnofsky performance status (KPS), tumor histology, history of whole brain radiation therapy, history of IMRT, history of craniotomy, date of death or last clinical contact, and age at initial SRS treatment. Treatment characteristics were obtained from the treatment plans, including tumor volume, prescription dose, prescription isodose, and maximum dose. Actuarial patient survival was defined as the time in months from initial SRS treatment to date of death or date of last clinical contact. The overall survival was calculated from date of first SRS treatment session to date of death or progression via the Kaplan-Meier method. At the time of initial treatment, 14% of patients were categorized as RPA class I, 71% as RPA class II, and 15% as RPA class III. Five patients were ALK positive,43 were ALK-negative. Nineteen patients were EGFR positive and 44 were EGFR negative. Results The median overall survival was 13.2 months. The Kaplan- Meier overall survival estimates at 6 and 12 months were 81.4% and 52.8%, respectively. There was a significant difference in survival between adenocarcinoma vs. squamous histology, 14.3 months vs. 8.1 months (p-value = 0.013). Patient pre-treatment RPA class was predictive of survival (p-value = 0.047). The median survival was 39.8 months for RPA class I, 12.8 months for RPA class II, and 7.5 months for RPA class III. The median survival for inactive ECD was 15.3 months and 11.5 months for inactive ECD (p-value= 0.034). Concurrent or prior WBRT, age, ALK mutation status, EGFR status, and KPS did not have a significant impact on survival following SRS. Conclusion SRS is an important modality in the management of discrete brain metastatic disease. Survival following SRS for NSCLC brain metastases varies widely, and the prognosis may depend on a broad range of tumor and patient parameters. Among our patient group, those with adenocarcinoma versus squamous histology, inactive extracranial disease status, and favorable RPA class had the longest overall survival. Prior or concurrent WBRT, age, ALK mutation status, EGFR status, and KPS were not predictive of survival. EP-1132 Hypofractionated Stereotactic Reirradiation for Recurrent High-grade Glioma L. Hynkova 1 , P. Slampa 1 , T. Kazda 1 , J. Garcic 1 , M. Vrzal 1 , P. Fadrus 2 , R. Belanova 3 , I. Sikova 4 , D. Dvorak 1 , H. Dolezelova 1 , P. Pospisil 1 1 Masaryk Memorial Cancer Institute, Clinic of Radiation Oncology, Brno, Czech Republic 2 The University Hospital Brno, Department of Neurosurgery, Brno, Czech Republic 3 Masaryk Memorial Cancer Institute, Department of Radiology, Brno, Czech Republic

4 Masaryk Memorial Cancer Institute, Department of Neurology, Brno, Czech Republic Purpose or Objective The treatment for recurrent high-grade glioma is diversified. In this retrospective analysis, we evaluated outcomes of stereotactic hypofractionated radiotherapy (SRT) in patients re-treated for reccurent high-grade glioma. Material and Methods From July 2004 to April 2013, 27 patients were treated. At the initial diagnosis, all patients underwent open-surgery resections to remove maximum of their tumors. SRT was performed with multileaf microcollimator systems (BrainLab) for linear accelerator. The dose given ranged from 16–25 Gy in a median five fractions (range, 1–5 fractions). The median volume of the tumor was 5,1 cm 3 (range, 0,03–33,7 cm 3 ). All the patients were treated with radiotherapy previously (range dose 50–60 Gy). Only patients with Karnofsky performance Status (KPS) > 60 were re-irradiated. The median age was 46 years (21–58). 9 patients (33 % ) had a glioblastoma diagnosis and 18 patients (67 %) were affected by grade III glioma (anaplastic astrocytoma/anaplastic oligoastrocytoma). After reirradiation 18 patients (67 %) received chemotherapy and 8 patients (30 %) received study of dendritic cells. Results The median overall survival from the date of salvage stereotactic radiotherapy was 13,9 months (95% CI 7,7– 20,5 months) with the range of follow-up from 2,9 to 128,9 months and the median overall survival following initial treatment was 46,8 months (95% CI 32–121,4). The survival was significantly shorter in the subgroup of patients with grade IV gliomas (p < 0,0036, HR 7,45, 95% CI: 1,62–34,31). From the date of stereotactic radiotherapy, the 1-year, 3- year and 5-year overall survival was 50,2 % (95% CI 33,7– 77,4%), 20,9 % (95% CI 9,6–45,6 %) and 12,5 % (95% CI 4,4– 36,1 %), respectively. The patients who underwent resection of subsequent post-stereotactic radiotherapy recurrence had better survival (p < 0,0142, HR 4,377, 95% CI:1,23-15,55). The increased survival was also observed in patients with longer intervals between initial treatment and stereotactic reirradiation (p < 0,0205, HR 0,984 95% CI: 0,07–1,0). The radiological response to reirradiation evaluated by MRI has not been a predictor of survival. No severe toxicity was recorded (any case of radionecrosis). Conclusion In our experience, hypofractionated stereotactic radiation therapy could be a safe and feasible option for recurrent high grade glioma. EP-1133 Multifraction Radiosurgery for Large Brain Metastasis: Initial Results from Brazilian Experience. A. Borges 1 , L. Ercolin 1 , M. De Mattos 1 , J. Alexandre 1 , M. Giglioli 1 , A. Camargo 1 , D. Marconi 1 , D. Fonseca 1 , T. Kaprealian 2 1 Barretos Cancer Hospital, Radiation Oncology, Barretos, Brazil 2 UCLA, Radiation Oncology, Los Angeles, USA Purpose or Objective To evaluate the clinical outcomes with linear accelerator- based multifraction stereotactic radiosurgery (mSRS), 3 fractions, to treatment of the large Brain Metastasis in Patients with brain metastases were included with 30 days or more of the end of the mSRS, between May 2015 to August 2016. The primary endpoint was acute toxicity and the secondary endpoints were overall survival, local control (in field) and Regional recurrence free survival. Prognostic factors were analyzed, as Ds-GPA, RPA, the number of treated lesions, the major lesion, time between the last Brazilian Population. Material and Methods