Volumetric extent of resection and survival for recurrent atypical meningioma.

OBJECTIVE: In recurrent atypical meningioma, the survival impact of volumetric extent of resection (vEOR) and residual tumor volume (RTV) has not been previously studied. METHODS: The authors performed a retrospective vEOR analysis of patients with recurrent World Health Organization grade II meningiomas treated with reresection from 2000 to 2019. The Kaplan-Meier method and multivariate Cox regression analysis were used to study progression-free survival (PFS) and overall survival (OS). RESULTS: Fifty-nine patients with a median follow-up duration of 95 (95% CI 42-148) months were included. The median (range) vEOR was 100% (32%-100%) and the mean ± SD was 90.7% ± 15.3%. Among patients who underwent gross-total resection (GTR) (n = 32 [54%]), Simpson grade I and II resections were achieved in 23 (72%) and 9 (28%) patients, respectively. Among patients who underwent subtotal resection (n = 27 [46%]), the median (range) RTV was 4.3 (0.3-40) cm3. The 1-, 2-, and 5-year actuarial PFS rates for the cohort were 76%, 56%, and 34%, respectively. The 1-, 2-, and 5-year actuarial OS rates for the cohort were 98%, 78%, and 60%, respectively. Variables reflecting EOR significantly impacted both PFS and OS in multivariate analysis: GTR (p < 0.01) was significantly associated with longer PFS, and lower Simpson grade (p = 0.04) was significantly associated with longer OS. Additional factors including RTV, Ki-67 index, and pretreatment and posttreatment history also impacted survival outcomes (p < 0.05). CONCLUSIONS: EOR and Simpson grade were independently associated with survival outcomes in patients with recurrent atypical meningioma. These findings support the practice of thorough reresection for maximal cytoreduction in appropriate surgical candidates.