ESTRO 2021 Abstract Book

S865

ESTRO 2021

D. Tomasini 1 , L. Triggiani 1 , S. Pedretti 2 , M.L. Bonù 1 , L. Costa 2 , L. Pegurri 2 , L. Romano 1 , N. Singh 1 , S. Lamattina 1 , E. Pastorello 1 , G. Facheris 1 , O. Turla 3 , P. Borghetti 2 , M. Buglione Di Monale E Bastia 1 , S.M. Magrini 1 1 university And Spedali Civili, Radiation Oncology Department, Brescia, Italy; 2 Spedali Civili, Radiation Oncology Department, Brescia, Italy; 3 University and Poliambulanza Hospital, Radiation Oncology Department, Brescia, Italy Purpose or Objective Purpose: hypofractionated radiation therapy (HRT) represents an alternative to conventional fractionation radiation therapy for elderly patients affected by glioblastoma. The aim of this study was to assess if HRT could provide adequate rates of overall survival (OS) in non-elderly patients with poor prognosis such as poor Karnofsky Performance Status (KPS) and minimal to no surgery. Materials and Methods Materials and methods: medical reports of 39 patients aged 70 years or less treated at the Radiation Oncology Department of the Spedali Civili (Brescia, Italy) with HRT were retrospectively reviewed. When feasible, patients underwent upfront surgery and were subsequently treated with HRT (40 Gy/15 fractions), usually starting adjuvant treatment within 4-6 weeks after surgery. If surgery was not practicable, patients underwent upfront HRT. TMZ was administered in different combinations, concomitantly to RT (75 mg per square meter of body-surface area per day, 7 days per week from the first to the last day of radiotherapy) and/or up to a maximum of 12 cycles after the end of RT (150 to 200 mg per square meter for 5 days during each 28-day Results: Median age at presentations was 63 years (range 34-70), KPS was 70 or less in 18 patients. RPA class at presentation was more frequently IV-V (79% of patients). Only 14 patients (36%) underwent gross or partial resection whereas in 25 patients (64%) surgery was not performed. MGMT metilation status was available in 26 patients: MGMT was metilated in 77% of them. IDH1 and IDH2 mutation was available in 34 patients and the status of the gene was wild type in the whole cohort. Chemotherapy with TMZ was performed in 74% of the whole population: concomitant TMZ was administered in 23 patients (59%) up to 3 cycles. Adjuvant chemotherapy was administered in 23 patients (59%): 3 or less cycles were administered in 14 patients (36%), 3 to 6 cycles were administered in 5 patients (13%) and only 4 patients (10%) underwent more than 6 cycles of adjuvant TMZ. Median follow up of the cohort was 9 months (range 2-48 months). Median OS was 8.1 months and is depicted in Figure 1 (IC 95% 5.9 – 10.2 months). Acute symptomatic headache and nausea (grade 2 or less) were reported in 20% and 6% of the patients, respectively. No acute grade 3-5 toxicity was reported. Twenty-four patients were able to perform at least one MRI during the follow up. One asymptomatic case of MRI radiation necrosis was reported (6 months after HRT). Radiation induced leukoencephalopathy was reported in 4 patients (10%). At univariate analysis, only good KPS and maximal-safe resections positively influenced OS. cycle). Results

Conclusion Conclusions: our data are in line with current literature and support the hypothesis that HRT could be offered to non-elderly poor prognosis patients without detrimental impact on OS and without increasing the risks of acute toxicity. Hopefully, these results could provide the basis to a larger prospective randomized trial. PO-1038 Radiotherapy with Temozolomide for Pediatric Glioblastoma:A single institute retrospective analysis. K. Ratanchandani 1 , S. Kunikullaya 2 , A. Parikh 2 , M. Mehta 3 , S. Patel 3 , V. Shivhare 3 , S. Rath 2 , V. Modi 2 , H. Jain 2 , D. Anand 3 , N. Bathija 3 1 The Gujarat Cancer and Research Institute, Radiation Oncology, Ahmedabad , India; 2 The Gujarat Cancer and Research Institute , Radiation Oncology, Ahmedabad , India; 3 The Gujarat Cancer and Research Institute , Radiation Oncology , Ahmedabad , India Purpose or Objective Glioblastoma in children is rare (6% pediatric CNS tumors). Pediatric glioblastoma (pGBM) patients are relatively less studied due to paucity of such patients. Role of temozolomide (TMZ )in adults is well