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

ABSTRACT

OBJECTIVE: 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. METHODS: Clinical data from 23 cases of PM and RM between January 2011 and December 2015 were retrospectively reviewed. RESULTS: 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). CONCLUSIONS: 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.