ESTRO 2020 Abstract book

S509 ESTRO 2020

toxicity and compliance limits its use. Temozolomide (TMZ) is widely used as an alternative. We aimed to evaluate the role of TMZ in the management of AOG patients treated at our institution retrospectively. Material and Methods Data of 48 AOG patients treated at our institution between 2012-2018 were retrieved from our departmental archives. All patients underwent a maximal safe resection with a confirmed histology of AOG. Post-operative radiotherapy (PORT) consisted of 60 Gray in 30 fractions delivered with 3-dimensional conformal radiotherapy on a linear accelerator. TMZ (75 mg/m 2 daily) was used during concurrent phase and 150-200 mg/m 2 was used during adjuvant phase (150 mg/m 2 in first cycle and then escalated to 200 mg/m 2 ) if tolerated well. Kaplan Meier method was used for survival analysis. Results Median age of the patient was 46 years (30-65 years). Male: Female ratio was 40:8. 22 (45.8%) patients presented with seizure. 31 (64.5%) patients underwent a gross total excision, 11 (22.9%) had a subtotal resection and 6 had decompression only. Median MIB labelling index was 24 (range: 6-43). 1p/19q co-deletion status was available in 20 (41.6%) patients and was co-deleted in 16 (80%) of these patients. Median radiotherapy dose was 60 Gray (range 46- 60 Gray). 29 (60.4%) patients received concurrent, 24 (50%) received both concurrent and adjuvant and 5 received only adjuvant TMZ. Median number of adjuvant TMZ cycles were 6 (range: 2-12). Rates of grade III-IV thrombocytopenia and neutropenia in patients receiving TMZ was 13.8 % and 6.89% patients respectively. Median follow up was 28 months. Estimated median progression free survival (PFS) was noted to be 4.8 years. 3-year progression free survival (PFS) and overall survival was 68% and 76% respectively. Univariate analysis revealed better PFS for patients presenting with seizure (HR=0.74; 95% CI: 0.64-0.89; p=0.038). Rest of the factors like age, extent of surgery or 1p/19q co-deletion status did not statistically impact survival. Conclusion Adjuvant and Concurrent TMZ is feasible and tolerable in patients of AOG treated with maximal safe resection and PORT. Results of randomized trial evaluating PCV versus TMZ in this setting would better allow us to tailor our treatment. Adaptation of management as per molecular profile of AOG is evolving. PO-0863 Radiochemotherapy retreatment in high grade giomas recurrences A. Caroli 1 , L. Vinante 1 , P. Chiovati 2 , T. Ius 3 , M. Skrap 3 , M. Arcicasa 1 1 IRCSS CRO Aviano, Department of Radiotherapy, Aviano, Italy ; 2 IRCSS CRO Aviano, Medical Physics, Aviano, Italy ; 3 Azienda Sanitaria Universitaria Integrata di Udine, Neurosurgery, Udine, Italy Purpose or Objective Glioblastoma is the most common primary malignant brain tumor in adults, counting 16% of all primary CNS tumors, with poor prognosis. Almost all patients undergo disease progression/recurrence: actually no standard of care is established for recurrent or progressive GBM (rGBM). Treatment approaches for tumor recurrences include second surgery, re-irradiation, systemic therapies, combined modality and supportive cares and have to consider tumor size and location, previous treatments, age, Karnofsky performance score (KPS), patterns of relapse, and prognostic factors. We retrospectively investigated the feasibility of a second irradiation with or without chemotherapy for these patients. Material and Methods From January 2011 until March 2018, thirty patients with recurrence of high-grade gliomas (12 with grade III gliomas, 18 with grade IV gliomas) received a median re- irradiation dose of 36 Gy (Range 34 – 41.1 Gy) with

such patients develop brain metastases (BMs). The survival benefit from hormonal and targeted therapy urges to treat patients with BMs with minimal toxicity and less systemic interruption. Here we assessed survival outcomes in patients who received upfront stereotactic radiosurgery (SRS). Material and Methods We retrospectively reviewed 196 patients who received upfront SRS for BMs from metastatic BC at MD Anderson Cancer Center in August 2009 ‒ May 2018, of whom 71 had triple-negative (TN), 56 luminal A, 35 luminal B, 31 HER2, and 3 unknown molecular subtypes. Primary endpoints were overall survival (OS) from BM diagnosis and time to salvage (TTS) and were estimated by Kaplan-Meier survival analysis. Cox proportional hazard regression analysis was used to identify prognostic factors. Results Median age at BM diagnosis was 52 y (range 24 ‒ 82); median Karnofsky Performance Score (KPS) was 90 (range 60 ‒ 100); and median number of BMs treated was 2 (range 1 ‒ 18). At a median follow-up time of 13.1 months (mo) for all patients (range 1.47–111.3 mo; 21.9 mo for patients alive at last follow-up), the median OS time was 15.7 mo. Factors associated with OS on multivariate analysis (MVA) were subtype (11.8 mo for TN, 13.7 mo for luminal A, 35.7 mo for luminal B, and 28.3 mo for HER2, p =0.003), KPS (1.5 mo for 60, 5.97 mo for 70, 10.0 mo for 80, 18.1 mo for 90, and 20.9 mo for 100, p =0.003) and receipt of salvage therapy ( p =0.008). Of the 102 patients (52%) who received salvage therapy after initial SRS, 61 received salvage whole-brain radiation therapy (WBRT) and 41 received salvage SRS. The median TTS was 6.7 mo (range 0.6 ‒ 63 mo). The 12-month salvage rate was 18.8% for WBRT and 24.5% for SRS. Patients who received salvage SRS had better OS than those who received salvage WBRT or SRS+WBRT (47.6 mo for salvage SRS, 15.1 mo for salvage WBRT, and 28.8 mo for SRS+WBRT, p <0.001). On MVA, OS was worse for those received salvage WBRT vs. salvage SRS (hazard ratio 4.6, p =0.06). Number of BMs treated by initial SRS did not affect OS (17.1 mo for <4 [n=151 patients] vs. 12.1 mo for >/= 4 [n=45 patients], p =0.4). Receipt of hormonal or HER2 therapy after BM diagnosis was associated with improved OS on univariate but not MVA. Conclusion Patients who received upfront SRS for BMs from BC had median OS of 15.7 mo and TTS of 6.7 mo. Molecular subtypes luminal B and HER2, good KPS, and possibly receipt of targeted or hormonal therapy predicted better OS. Number of BMs treated by upfront SRS was not associated with OS. Salvage SRS is associated with better OS compared to WBRT and this may reflect patient selection. Prospective studies are needed to clarify the best treatment strategies for the various subgroups of patients with BMs from BC particularly in the era of increasing use of new systemic therapies. PO-0862 Clinical outcome of anaplastic oligodendroglioma treated with adjuvant radiotherapy and temozolomide M. Rastogi 1 , A. K Gandhi 1 , R. Khurana 1 , R. Hadi 1 , S. Sapru 1 , S. P Mishra 1 , A. K Srivastava 1 , A. Bharati 1 , S. Rath 1 , S. S Nanda 1 , H. B Singh 1 , S. Kumar 1 , N. P Singh 1 , N. Husain 2 , M. Husain 3 , D. K Singh 4 1 Dr. Ram Manohar Lohia Institute of Medical Sciences, Radiation Oncology, Lucknow, India ; 2 Dr. Ram Manohar Lohia Institute of Medical Sciences, Pathology, Lucknow, India ; 3 Sahara Hospital, Neurosurgery, Lucknow, India ; 4 Dr. Ram Manohar Lohia Institute of Medical Sciences, Neurosurgery, Lucknow, India Purpose or Objective Anaplastic oligodendroglioma (AOG) are diverse group of tumors with variable molecular profiles. Although, PCV chemotherapy has been shown to improve outcome,