Stereotactic Radiosurgery for Resected Brain Metastases: Single-Institutional Experience of Over 500 Cavities.

Purpose: Postoperative stereotactic radiosurgery (SRS) has less detrimental effect on cognition and quality of life compared with whole brain radiation therapy (WBRT) and is increasingly used for resected brain metastases (BMs). Postoperative SRS techniques are not standardized, and there is a concern for a different pattern of failure after postoperative SRS compared with WBRT. We aim to study the efficacy, toxicity, and failure pattern of postoperative SRS.

Methods And Materials: We retrospectively reviewed outcomes of patients with resected BMs treated with postoperative SRS between 2007 and 2018. Overall survival and cumulative incidences of local failure, overall distant intracranial failure (distant parenchymal failure, nodular leptomeningeal disease [nLMD], classical leptomeningeal disease [cLMD]), and adverse radiation effect were reported. Neurologic death was determined for patients with leptomeningeal disease (LMD).

Results: A total of 442 patients with 501 resected BMs were treated over 475 total SRS courses. Median clinical follow-up and overall survival after SRS were 10.1 months (interquartile range, 3.6-20.7 months) and 13.9 months (95% confidence interval [CI], 11.8-15.2 months), respectively. At 12 months, event rates were 7% (95% CI, 5%-10%) for local failure, 9% (95% CI, 7%-12%) for adverse radiation effect, 44% (95% CI, 40%-49%) for overall distant intracranial failure, 37% (95% CI, 33%-42%) for distant parenchymal failure, and 13% (95% CI, 10%-17%) for LMD. The overall incidence of LMD was 15.8% (53% cLMD, 46% nLMD). cLMD was associated with shorter survival than nLMD (2.0 vs 11.2 months, P < .01) and a higher proportion of neurologic death (67% vs 41%, P = .02). A total of 15% of patients ultimately received WBRT.

Conclusions: We report the largest clinical experience of postoperative SRS for resected BMs, showing excellent local control and low toxicity. Intracranial failure was predominantly distant, with a rising incidence of LMD.