ESTRO 2022 - Abstract Book

S973

Abstract book

ESTRO 2022

Results The median follow-up for all patients was 9,4 months (2,1-24,2). The most frequently histology was NSCLC (50%) followed by renal cancer (25%), mean age was 71 years (42-87). OS at 10 months of 79,5% and PFS of 52% at 10 months. The median planning target volume (PTV) was 5,7cc (range 47,1-0,9 cc). In the statistical analysis with IBM v.24, ANOVA analysis showed no statistical relationship between irradiated brain volume (V25 and V30) (p 0,8/0,3) or PTV volume (p 0,9) and time to relapse. A significative tendency between volume PTV and OS was observed. No severe toxicities were observed. The 50% of the patients presented in the first control a median reduction edema 19,6 cc (4,5-66cc) 66% of them could reduce the steroids dose after treatment. The major volume of PTV was linked with a minor edema reduction in the first image control. Conclusion Our study suggests no significative statistical relationship between brain volume irradiated or PTV and OS or PFS. 50% of patients reviewed experimented significative reduction of the edema volume in the MRI at 3 months after treatment. The 66% of the patients could reduce steroids dose. Hypofractionated scheme is a safe option of treatment for brain metastasis with impact over the reduction in steroids dose and brain edema after treatment. G. Ferraris 1 , L.D.L.A. Alvarado 2 , A.M. Gomez Palacios 1 , L. Caussa 1 , M.F. Diaz Vazquez 1 , D. Fernandez 1 , O. Perez Conci 1 , L. Brun 1 1 Centro de Radioterapia Dean Funes, Radiotherapy, Cordoba, Argentina; 2 Hope International Institute, Radiotherapy, Guatemala, Guatemala Purpose or Objective To report toxicity and survival outcomes, obtained in non-elderly patients with malignant gliomas, treated with hypofractionated radiotherapy (HFRT). Materials and Methods A retrospective analysis was performed, of 67 non-elderly patients with malignant gliomas, treated in Centro Médico Dean Funes Córdoba, Argentina, from September 2016 to October 2019. Treatment volume was contoured using brain MRI, which was fused with institutional computed tomography, in stereotactic conditions, and planned with IMRT. Total prescribed dose to target volume was between 35–54Gy, which was administered using three different hypofractionated schemes: 10, 15 or 20 continuous fractions, of 2.7–5 Gy. Treatment was delivered with 6MV photon beams of a Linear Accelerator, using IGRT ConeBeamCT. Acute and chronic toxicity was assessed according to CTCAEv4.0. Survival outcomes were obtained with Kaplan Meier survival analysis. Results At a median follow up of 15 months, 41 (61%) patients were men and 26 (39%) were women, with a median age of 50, and a median KPS of 87. Glioblastoma multiforme was the most common histological type in 34 (51%) patients, followed by astrocytoma in 26 (39%) and oligodendroglioma in 7 (10%). 28 (42%) patients underwent total resection, 31 (46%) partial resection, and 8 (12%) biopsy only. Concurrent Temozolamide (TMZ) was administered to 76% of patients. All patients completed treatment, 78% without breaks, and 22% with 1-3 breaks. The most common acute adverse events were: G1 headache (27%), alopecia (14%), G1 fatigue (11%), and G1 epidermitis (11%). The most commonly registered chronic adverse events were: cognitive deficit (23%), partial seizures (23%), and vision change (15%). Acute toxicity was higher in the 20 fractions scheme (50%), while chronic toxicity was higher in the 10 fractions scheme (56%). Overall survival (OS) was of 94%, 90%, 75%, and 53% at 3, 6, 12, and 24 months respectively. 36 (54%) patients were still alive at last follow up. Progression free survival (PFS) was of 92%, 77%, 54%, and 44% at 3, 6, 12, and 24 months, respectively, reaching median PFS at 15 months. Treatment volumen <290 cc and total or partial resection showed better OS and PFS; Concurrent TMZ showed better OS; however, in univariate and multivariate analysis, none proved to be a survival predictive factor. At univariate analysis, age > 50 (p=0.009) and KPS <90 previous to HFRT (p=0.019) , and KPS <90 at the end of HFRT (p=0.004) , were associated with worse OS. While in multivariate analysis only age >50 (RR 2.71 p= 0.030) and KPS <90 at the end of HFRT (RR 6.08 p=0.001], proved to be worse OS predictive factors. PO-1147 Hypofractionated RT for non-elderly patients with malignant gliomas: Institutional experience

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