Revisiting oligodendroglioma prognosis: Influence of recent WHO classification on patient outcomes by comparative analysis of progression-free survival in an Indian cohort

Abstract Background: Oligodendrogliomas are rare primary central nervous system (CNS) tumors characterized by isocitrate dehydrogenase (IDH) mutation and 1p/19q codeletion, as redefined in the recent World Health Organization (WHO) classification. This study evaluates progression-free survival (PFS) in oligodendroglioma patients diagnosed with and without molecular testing. Aim: This study aimed to evaluate and compare PFS and recurrence rates among patients diagnosed with and without the adoption of molecular diagnostics, highlighting the impact of the recent WHO classification. Settings and Design: It is a prospective observational study. Materials and Methods: A prospective observational study was conducted from 2019 to 2023 on 30 patients with WHO grade 2 oligodendrogliomas, categorized into two groups: Group A (only histopathology) and Group B (histopathology + molecular testing). PFS was compared using Kaplan–Meier survival analysis and statistical tests. Statistical Analysis Used: PFS was analyzed using Kaplan–Meier survival curves, and statistical significance was assessed using the Mann–Whitney U test ( P < 0.05). Results: Group B exhibited superior 2- and 5-year PFS (86.67% and 46.67%) compared with Group A (73.33% and 66.67%). Recurrence at 5 years was lower in Group B (6.67%) than in Group A (20%). Mean PFS was significantly higher in Group A (72.13 months) than in Group B (48.60 months; P = 0.048). Conclusions: Oligodendroglioma, a WHO grade 2 CNS tumor, typically presents in middle-aged adults with seizures and is commonly located in the frontal lobe. Optimal management includes maximal safe resection followed by adjuvant chemo-radiation. 1p/19q codeletion and IDH mutation are critical for prognosis and guiding treatment, with improved survival outcomes.