Beyond the surgical margin: Patterns of recurrence in WHO grade II intracranial meningiomas

Abstract

Abstract Purpose To characterize and classify the location of recurrence in surgically resected World Health Organization (WHO) grade II intracranial meningiomas that did not receive adjuvant radiation, and compare the recurrence pattern of those that underwent gross total (GTR) versus subtotal resection (STR). Methods A retrospective review of patients who underwent surgical resection of WHO grade II meningiomas at our institution between 2006 and 2019 was performed. Patients that were observed postoperatively without adjuvant radiation and subsequently developed a recurrence were included. Recurrence was defined as evidence of radiographic progression on postoperative surveillance MRI. Location of recurrence were categorized as: (1)central - growth observed inside the area of the previously resected tumor more than 1 cm inside the original tumor margin; (2)marginal - growth observed within 1 cm (inside or outside) of the original tumor margin; and (3)distant - growth observed more than 1 cm outside of the original tumor margin. Results A total of 22 patients matched the inclusion criteria. Twelve (55%) underwent GTR while ten (45%) underwent STR. Of the GTR patients, ten (83.3%) had central recurrence, 11 (91.7%) had marginal recurrence, and only 4 (33.3%) had distant recurrence. Of the STR patients, 9 (90.0%) had central recurrence, all 10 (100.0%) had marginal recurrence, and only 4 (40.0%) had distant recurrence. Conclusion The present study evaluating patterns of recurrence for WHO grade II meningiomas after surgical resection showed that recurrence occurred centrally and/or at the original tumor margin, with only a minority recurring > 1cm outside the original tumor margin.