ESTRO 2025 - Abstract Book

S643

Clinical - CNS

ESTRO 2025

30

Digital Poster Validation of the clinical practicability of the GPA for NSCLC patients with BMs treated with GKRS. Kiril Zhelev 1 , Manoela Cholakova 1 , Bilyana Korabova 1 , Maria Mihaylova-Hristova 2 , Nikolay Conev 3 , Mila Petrova 4 , Petya Kraleva 4 , Ivan Donev 4 , Iglika Mihaylova 5 1 Radiotherapy and Radiosurgery, Heart and Brain Center of Clinical Excellence, Pleven, Bulgaria. 2 Nuclear Medicine, Oncology Hospital, Sofia, Bulgaria. 3 Medical Oncology, UMHAT St Marina, Varna, Bulgaria. 4 Medical Oncology, MHAT Nadezhda, Sofia, Bulgaria. 5 Radiotherapy, Oncology Hospital, Sofia, Bulgaria Purpose/Objective: The purpose of this study was to confirm the graded prognostic assessment (GPA) for patients with brain metastases (BMs) of the lung treated with Gamma Knife radiosurgery (GKRS) and discuss its clinical practicability. Material/Methods: In this single study, we analyzed 104 patients with BMs from NSCLC in the period between January 2021 and February 2023, of which 74 (71.2%) were with adenocarcinoma, 19 (18.3%) were with squamous, 6 (5.8%) were with large cell, and 5 (4.8%) had another type of histology. We calculated the lung-molGPA, a disease-specific GPA for NSCLC. We calculated the overall survival for each GPA group. We also compared the expected and actual OS in the prognostic groups of the GPA available at the time of the patients' diagnosis. We used Kaplan-Meier and Cox regression models for survival analysis. Overall survival (OS) was defined as the interval between GKRS treatment of the disease and death, or the date of the last follow-up evaluation. Results: The cohort included 65 men (62.5%) and 39 women (37.5%), with a total mean age of 64±5 years. Patients with Karnofsky Performance Status (KPS) 90 were 36 (34.6%), KPS 80–39 (37.5%), and KPS 70–29 (27.9%). Patients with extracranial metastasis (ECM) were 84 (80.8%), and those without were 20 (19.2%). The mean overall survival (OS) from the diagnosis of brain metastases was 19 months (95% confidence interval (CI) 15.5–22.5 months). The mean OS in the three individual prognostic groups was 5.4 months for GPA 0-1, 10.7 months for GPA 1.5-2, 24.8 months for GPA 2.5-3, and 33.7 months for GPA 3.5-4, where in some patients it was not reached (p<0.001). When comparing the expected and actual OS, there was an overestimation of more than three months for the well prognosis group based on the available GPA at the time of diagnosis. Conclusion: We were able to validate the GPA for NSCLC patients with brain metastases treated with GKRS. However, given the always-changing landscape of treatments and the steady improvement in overall survival, the practical application of the projected median OS may be limited.

Keywords: GPA, GKRS, Brain metastases

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Digital Poster Postoperative radiosurgery (SRS) vs hypofractionated stereotactic radiotherapy (HFSRT) for resected brain metastases – a single centre analysis Lena Kretzschmar 1 , Hubert Gabrys 1 , Anja Joye 1 , Johannes Kraft 2 , Matthias Guckenberger 1 , Nicolaus Andratschke 1 1 Department of Radiation Oncology, USZ University Hospital Zurich, Zurich, Switzerland. 2 Department of Radiation Oncology, KSA Kantonsspital Aarau, Aarau, Switzerland