Extended adjuvant temozolomide improves survival in glioblastoma: An 8-year experience from a South Indian regional cancer centre

Abstract

Background: Glioblastoma (GBM) remains the most aggressive primary brain tumour with a dismal prognosis despite multimodal therapy. The optimal duration of adjuvant temozolomide (TMZ) remains debated. Methods: A retrospective analysis was conducted on 110 histologically confirmed GBM patients treated between January 2017 and June 2025 at Kidwai Memorial Institute of Oncology. All underwent maximal safe resection followed by radiotherapy with concurrent TMZ (75 mg/m 2 ). Post-radiation, patients received six cycles (Arm B, n = 55) or twelve cycles (Arm A, n = 55) of adjuvant TMZ. Endpoints were overall survival (OS), progression-free survival (PFS), toxicity, and compliance. Results: Median follow-up was 28 months. Median OS was 20.5 months (Arm A) vs 17.5 months (Arm B) ( p = 0.02); median PFS was 11.8 vs 9.2 months ( p = 0.04). Two-year OS was 32% vs 21%. Grade 3-4 haematologic toxicity occurred in 16% and 14% ( p = 0.72). Conclusion: Extending adjuvant TMZ to 12 months provided a modest but statistically significant survival improvement (~3 months) without increased toxicity. This large single-centre South Indian dataset adds valuable real-world evidence to the global debate on optimal TMZ duration.