ESTRO 2025 - Abstract Book

S756

Clinical - CNS

ESTRO 2025

4325

Digital Poster Evaluating the Impact of Adjuvant Temozolomide Duration on Survival Outcomes in Low-Grade Gliomas: A Clinical audit from tertiary care centre Arnav Tiwari, Narendra Kumar, Renu Madan, Harishmita Devi, Dharmendra Shah Radiotherapy and Oncology, PGIMER, Chandigarh, India Purpose/Objective: Low-grade gliomas (LGGs) represent a subgroup of brain tumors with indolent progression yet significant risks of recurrence. Adjuvant temozolomide (TMZ) chemotherapy is increasingly used to enhance survival outcomes.The optimal duration of adjuvant chemotherapy and its differential impact on LGG subtypes remain uncertain. Objectives 1. To assess the survival benefit of adjuvant TMZ chemotherapy in LGG patients. 2. To evaluate whether extending adjuvant chemotherapy beyond six months improves overall survival. 3. To analyze subtype-specific survival outcome. Material/Methods: In this retrospective study all patient data from 2014 to 2020 was extracted. Patients with the diagnosis of low-grade glioma were recorded. Information regarding the histology, diagnosis, radiotherapy, concurrent and adjuvant therapy was recorded. Patient’s last follow up date was recorded. patients with last follow up more than 6 months ago were telephonically contacted and updated. Patients were categorized into treatment groups: radiotherapy only (XRT), radiotherapy with concurrent and/or adjuvant chemotherapy (XRT+CCT, XRT+CCT+ACT, or XRT+ACT), and no adjuvant treatment. Patients receiving adjuvant chemotherapy were classified into two groups (less than or equal or more than 6 months of Temozolomide). Survival outcomes were compared using Kaplan-Meier survival estimates and statistical tests, including the Log Rank and Kruskal-Wallis tests. The Kruskal-Wallis test confirmed the significance of survival differences by treatment duration ( p < 0.001). Results: There were 578 patients with low-grade glioma registered out of which 416 patients were evaluable (histology review and completeness of data). The treatment distribution was as follows: • XRT+CCT+ACT: 63 (15.1%) • XRT+CCT: 33 (7.9%) • XRT only: 211 (50.7%) • XRT+ACT: 28 (6.7%) • No adjuvant treatment: 81 (19.5%). Patients receiving six or more months of adjuvant TMZ chemotherapy demonstrated superior survival (median: 1496 months, 95% CI [812.302–2179.698]) compared to those receiving less than six months (median: 272 months, 95% CI [191.310–352.690]) or no adjuvant chemotherapy (median: 422 months, 95% CI [279.331–564.669]). In Subgroup analysis: • Astrocytomas : Median survival was longest in the ≥6 months adjuvant group (1793 months), with significantly poorer outcomes for patients receiving <6 months of chemotherapy (231 months). • Oligodendrogliomas : Median survival was highest in the ≥6 months adjuvant group (1312 months), with shorter survival for <6 months of chemotherapy (302 months).