Any RHYTHM to the Recurrence? A Pattern of Recurrence Analysis in Surgically Resected Who II Intracranial Meningiomas

Objective: Recurrence after surgical treatment of meningiomas remains a challenge, especially in higher grade meningiomas. For intracranial WHO grade II meningiomas that are resected, there is no clear understanding concerning the patterns of recurrence. Specifically, the proximity of the recurrence to the resected margin is poorly understood. This study characterizes the patterns of recurrence in resected WHO grade II intracranial meningiomas, classifying and comparing the recurrence patterns of those that underwent complete or subtotal resection.

Methods: A retrospective review of patients who underwent surgical treatment of newly diagnosed WHO grade II meningiomas at our institution between 2006 and 2019 was performed. All patients who received adjuvant therapy were excluded such that our patient population consisted of only surgically treated patients. Recurrence was defined as any evidence of radiographic progression on postoperative surveillance MRI. Patterns of recurrence were defined as follows: (1) “zone 1: central” recurrence (growth observed inside the area of the previously resected tumor, more than 1 cm from the margin); (2) “zone 2: marginal” recurrence (growth observed within 1 cm of the previously resected tumor margin); and (3) “zone 3: remote” recurrence (growth observed more than 1 cm outside of the previously resected tumor margin). Patterns of recurrence were evaluated by a neurosurgery fellow and a neurosurgery resident independently by co-registering pre- and postoperative MRIs using the BrainLab software, and any differences were reconciled by discussion.

Results: A total of 22 patients matched the inclusion criteria. Twelve (55%) underwent GTR, while ten (45%) underwent STR. In 12 patients in whom GTR was achieved, mean preoperative tumor volume was 50.6 cm³ with 5 (41.7%) in a skull base location. The average time to recurrence for these tumors was 22.7 months, with a mean recurrent tumor volume of 9.0 cm³ and 25 distinct tumor recurrence sites. Of these 25 recurrences, 10 (40%) recurred in zone 1, 11 (44%) recurred in zone 2, and only 4 (16%) recurred in zone 3.

In 10 patients in whom STR was achieved, mean preoperative tumor volume was 44.8 cm³, with 7 (70.0%) in a skull base location. The average time to recurrence for these tumors was 23.0 months, with a mean recurrent tumor volume of 21.8 cm³ and 23 distinct tumor recurrence sites. Of these 23 recurrences, 9 (90.0%) recurred in zone 1, 10 (100.0%) recurred in zone 2, and only 4 (40.0%) recurred in zone 3.

Conclusion: The present study evaluating patterns of recurrence for WHO grade II meningiomas after surgical resection (GTR or STR) showed that recurrence occurred mostly inside and at the original tumor margin, with only a minority recurring outside the original tumor margin.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
15 February 2022