Long-term outcomes of multimodality management for parasagittal meningiomas.

Purpose: The aim of this study was to systematically analyze the clinical characteristics of a large cohort of parasagittal meningioma (PM) and to evaluate the patients' outcomes and best treatment strategies based on tumor features.

Methods: To minimize selection bias we performed a single-institutional review of PM with restricted criteria. One hundred and ninety-two consecutive patients who met criteria for inclusion were reviewed from 2003 to 2011 in our general hospital.

Results: A total of 131 cases (68.2%) were with WHO grade I, while grade II and grade III PMs constituted 40 (20.8%) and 21 cases (10.9%). Higher histological grade was associated with loss of trimethylation of H3K27 (P = 0.000). For WHO grade I PMs, GTR was significantly associated with a better PFS (P = 0.023); however, adjuvant radiotherapy did not benefit patients with STR (P = 0.215). For de novo high-grade (WHO grade II and III) PMs (n = 37), adjuvant radiotherapy was associated with a significantly longer OS (P = 0.013), while no difference was observed between GTR and STR (P = 0.654). In recurrent high-grade PM patients (n = 24), GTR combined with adjuvant radiotherapy increased PFS (P = 0.005).

Conclusions: This study demonstrated that PMs were a heterogeneous group of tumors with a high proportion of high-grade tumors that often displayed aggressive clinical behaviors. Low-grade PM benefited from radical resection, whereas high-grade de novo PM did not. Adjuvant radiotherapy significantly prolonged OS for high-grade primary PM, but did not impact survival of patients with subtotally resected low-grade tumors. Long-term outcome of high-grade recurrent PMs was dismal. We thus show that extent of tumor resection, tumor grade and tumor recurrent status inform therapeutic decisions for PMs.