World Health Organization Grade III (Nonanaplastic) Meningioma: Experience in a Series of 23 Cases.

Abstract

Rhabdoid meningioma (RM) and papillary meningioma (PM) are rare variants of World Health Organization grade III meningiomas. In this study, we presented a series of 23 cases from our institution to investigate adverse factors of and appropriate treatment for RM and PM. Clinical data from 23 cases of PM and RM between January 2011 and December 2015 were retrospectively reviewed. The median follow-up was 38.0 months for World Health Organization grade III meningiomas. The mean progression-free survival (PFS) was 37.6 months, with 1-year, 3-year, and 5-year PFS of 78.3%, 50.8%, and 43.6%, respectively. The mean overall survival (OS) was 48.8 months, with 1-year, 3-year, and 5-year OS of 95.7%, 82.6%, and 44.0%, respectively. Univariate analysis showed that a ki-67 proliferation index >20% (hazard ratio [HR], 4.190; 95% confidence interval [CI], 1.033-17.001; P= 0.045) and PM (HR, 3.375; 95% CI, 0.998-11.408; P= 0.005) were related to worse PFS. Patients administered postoperative radiotherapy (PRT) after surgery had longer OS than did patients who did not receive PRT (median, 60.7 vs. 35.1 months; P= 0.029). Multivariate analysis showed that PRT was an independent factor for PFS (HR, 0.147; 95% CI, 0.033-0.657; P= 0.012) and OS (HR, 0.130; 95% CI, 0.025-0.691; P= 0.017) and that RM was an independent factor for PFS (HR, 7.312; 95% CI, 1.587-33.688; P= 0.011) and OS (HR, 6.447; 95% CI, 1.310-31.740; P= 0.022). We recommended adjuvant radiation regardless of the extent of resection. Individuals with PM or RM were at increased risk of recurrence and death; appropriate treatment for these patients should be further studied, and close follow-up is needed.