Intracranial Meningiomas: A Systematic Analysis of Prognostic Factors for Recurrence in a Large Single Institution Surgical Series

Background: Meningioma is the most common primary intracranial tumor. Surgical resection is the first choice of treatment, whereas the role of adjuvant radiotherapy (RT) is still unclear. Aim of the study was to evaluate prognostic factors influencing the local recurrence rate. Methods: Patients who had grade I-II meningiomas and underwent surgery were included in the present study. The extent of surgical resection was defined according to Simpson criteria, and were dichotomized as gross total and subtotal resection (STR). Adjuvant RT was considered in case of STR. Clinical outcome was evaluated by neurological examination and brain magnetic resonance imaging, which was performed every 6 months for the first year and yearly thereafter. Results: From January 2000 to December 2015, 296 patients were analyzed. Most were women (65.9%), with a Karnofsky performance status ≥80 (94.6%), grade I meningioma (79.4%), and symptoms at diagnosis (91.5%). STR was performed in 58%, followed by adjuvant RT in 10%. Improvement or stability of neurological status was obtained in 90.4% of patients. The median follow-up time was 79 months (range, 24–214 months). Local recurrence occurred in 87 (29.4%) patients, at a median time of 56 months (range, 6–214 months). No patients, who underwent surgery plus adjuvant RT, had local relapse. The median, 2-, 5-, 10-year progression-free survival were 172 months, 91.1%, 80.7%, and 67.2%, respectively. On univariate and multivariate analysis factors impacting on progression-free survival were grade, extent of surgical resection, and adjuvant RT in case of STR, regardless of meningioma grade. Conclusions: Overall, our findings suggest that recurrence rates are influenced by grade, extent of surgical resection, and use of adjuvant RT in not completely resected meningioma, regardless of tumor grade.