Impact of Resection on Survival of Isocitrate Dehydrogenase 1-Mutated World Health Organization Grade II Astrocytoma After Malignant Progression

OBJECTIVE: To evaluate the impact of surgical resection and adjuvant treatment on the course of patients after malignant progression of previously treated isocitrate dehydrogenase 1 (IDH1)-mutated World Health Organization (WHO) grade II astrocytoma. METHODS: This retrospective study explored 56 patients undergoing tumor resection for malignant progression after previously treated IDH1-mutated WHO grade II astrocytoma. We analyzed survival after malignant progression, analyzed overall survival (OS), and identified prognostic factors using Kaplan-Meier estimates and log-rank test. RESULTS: By the time of malignant transformation, median age was 44 years, and median Karnofsky Performance Status (KPS) score was 90. Complete resection of contrastenhancing tissue was achieved in 18 (32.1%) patients. Median survival after re-resection was 33 months (95% confidence interval [CI], 20-46); median OS was 123 months (95% CI, 77-170). Gross total tumor resection, postoperative KPS score >= 80, adjuvant radiochemotherapy, and prior radiotherapy significantly correlated with postmalignant progression survival. CONCLUSIONS: Patients in good clinical condition with malignant progression of previously treated low-grade gliomas should receive aggressive treatment, including re-resection.