Extent of resection and adjuvant radiotherapy in intracranial anaplastic meningioma: improved disease control with no statistically significant overall survival benefit

Abstract

Intracranial anaplastic meningioma, currently classified as World Health Organization (WHO) Grade III, is a rare and biologically aggressive tumor with a high recurrence rate. Due to its rarity, the available literature on its clinical characteristics and prognostic factors remains limited. In this study, we aimed to evaluate the relative impact of the extent of surgical resection and adjuvant radiotherapy on long-term survival and recurrence control in patients with intracranial anaplastic meningioma. We conducted a retrospective cohort study of patients with histopathologically confirmed World Health Organization (WHO) Grade III meningioma. Among 5,962 cases treated between January 2012 and July 2022, 46 patients with complete follow-up data were included. Clinical characteristics, treatment modalities, and outcomes were analyzed. Kaplan–Meier analysis was used to assess progression-free survival (PFS) and overall survival (OS). During follow-up, 38 patients (82.6%) experienced tumor recurrence. The median PFS was 24 months, with 2- and 5-year recurrence rates of 52.0% and 77.0%, respectively. The median OS was 68 months, with 2- and 5-year OS rates of 79.7% and 56.5%. Simpson Grade I/II resection was associated with longer OS than Grade III/IV resection, although the difference was not statistically significant. Adjuvant radiotherapy showed a trend toward improved OS but did not reach statistical significance. In contrast, radiotherapy was associated with delayed recurrence and prolonged PFS, particularly in terms of early recurrence control. Intracranial anaplastic meningioma is characterized by high recurrence and poor prognosis. In this cohort, neither extent of resection nor adjuvant radiotherapy reached a statistically significant improvement in overall survival, whereas both were associated with delayed tumor recurrence. These findings suggest that current treatment strategies may primarily provide temporal disease control rather than substantially altering long-term survival outcomes.