An evidence-based framework for postoperative surveillance of meningioma.

Background: Meningiomas frequently recur after surgery. Existing guidelines for postoperative surveillance are based on customary practices or limited data. This may result in excessive or inadequate surveillance. Methods: We compared 8 studies involving 1519 resected meningiomas with postoperative follow-up ranging from 7 to 23 years. Meningiomas were stratified using the World Health Organization and Simpson grading systems, and progression-free survival data were compared. Recurrence patterns were validated using 2 additional studies involving 2463 meningiomas. Results: Incompletely resected meningiomas of all grades displayed recurrences throughout the observation period. The 5-year and 10-year cumulative incidence of recurrence for completely resected Grade 1 meningiomas was 10% and 20%, with no recurrences beyond 11 years. For completely resected Grade 2 meningiomas, the 5-year and 10-year cumulative incidence of recurrence was 24% and 50%, with ongoing recurrences throughout the observation period. Elevated recurrence rates for Grade 1/2 meningiomas persisted beyond 5 years. For completely resected Grade 3 meningiomas, the 5-year cumulative incidence of recurrence was 63%, and all recurred before 10 years. Conclusions: Postoperative magnetic resonance imaging (MRI) at 48 h to determine the extent of resection and at 4 months to detect rapid regrowth is recommended. For completely resected Grade 1 meningiomas, annual MRI followed by discontinuation of surveillance if there is no recurrence after 11 years is reasonable. For completely resected Grade 2 meningiomas, annual MRI indefinitely is recommended. For Grade 3 meningiomas, MRI every 3-4 months for 2 years, followed by every 6 months indefinitely, is recommended. Incompletely resected meningiomas should be followed indefinitely.