Outcomes of Management of Progressive Radiosurgery-Treated Brain Metastasis With Resection Followed by Pathology-Informed Management: A Retrospective Study.

Background and objectives: In patients treated with stereotactic radiosurgery (SRS) for brain metastases, follow-up imaging demonstrating progression may result from treatment effect/radionecrosis (RN) or tumor progression. We report long-term outcomes for a cohort of patients who demonstrated radiological progression on serial imaging after initial radiation and who underwent resection, at which point histology informed further management.

Methods: A retrospective chart review identified 76 patients with an associated 82 brain lesions between 2009 and 2022, that were initially treated with SRS, and then demonstrated suspicious imaging developing through at least 2 scan time points with either pathologic confirmation of tumor or RN.

Results: Of the 82 lesions, 55 lesions (67.1%) were found to be tumor and were treated with repeat radiation and 27 (32.9%) were found to have pathologically confirmed RN and conservatively managed. 14/27 lesions ultimately found to be radionecrotic required steroids preoperatively due to neurological symptoms. None of these lesions required further intervention with median postsurgery follow-up of 24.4 months (range 1-104 months). There were 55 instances (in 51 patients) of confirmed recurrent/progressive tumor who we treated with repeat aggressive radiation with either Cs-131 brachytherapy (12 [21.8%]) or SRS (43 [78.2%]). Among patients treated with reirradiation, the median follow-up to local failure was 15.2 months (95% CI 7.3-26.6 months). The 2-year local control rate was 79.5% (95% CI 68.3%-92.5%).

Conclusion: These results support resection of radiosurgery-treated lesions with progression continuing through serial imaging, and this pathology-informed management results in excellent control of both RN and tumor progression after radiosurgery.