Reconsideration of the resection strategy of eloquent brain metastasis in the era of postoperative stereotactic radiotherapy: a comparative analysis with non-eloquent metastasis.

Purpose: To decrease the recurrence rate after complete resection of a brain metastasis, removal of a surgical safety margin is advocated. This is not always feasible when resecting a metastasis in an eloquent location. We aimed to assess the recurrence rate after resection of metastases in an eloquent location followed by postoperative stereotactic radiotherapy to the resection cavity.

Methods: We retrospectively included patients with 1-3 brain metastases undergoing gross total resection and postoperative stereotactic radiotherapy between 2010 and 2022. Primary endpoint was local recurrence free survival (LRFS). Secondary endpoints were overall survival and distant brain failure free survival. Patients were grouped according to the location of their metastasis into eloquent and non-eloquent. Eloquent localization was considered a surrogate for resection without a surgical safety margin according to our institutional practice.

Results: We included 193 patients with 201 resected metastases. Ninety-five metastases (47.3%) were classified as eloquent and 106 (52.7%) as non-eloquent. Kaplan-Meier analysis showed no difference in LRFS between eloquent and non-eloquent metastases (HR 0.821, 95%-CI 0.447-1.507, p = 0.523). Only increased preoperative tumor volume was associated with worse LRFS (HR 1.015, 95% CI 1.001-1.028, p = 0.033). There was no difference concerning secondary endpoints between eloquent and non-eloquent metastases.

Conclusion: Omission of a surgical safety margin in at least a part of the resection cavity due to eloquence of adjacent tissue had no detrimental effect on local control after resection and postoperative stereotactic radiotherapy of a brain metastasis. This could influence the strategy during resection of an eloquent metastasis.