Outcomes and adverse events of postoperative stereotactic interventional radiotherapy/brachytherapy for brain metastases: a systematic review

Abstract

Postoperative radiotherapy is commonly used after resection of brain metastases, but durable local control with a low rate of adverse events (AEs) remains challenging. This systematic review summarizes outcomes and AEs of postoperative stereotactic interventional radiotherapy (S-IRT; brachytherapy) for resected brain metastases. PubMed, Embase, Scopus, and Web of Science were searched through June 30, 2024. No review protocol was registered. Eligible studies reported postoperative S-IRT after metastasis resection. Data were extracted independently by two reviewers, with disagreements resolved by consensus. Risk of bias and methodological quality were assessed using the Newcastle–Ottawa Scale and MINORS. Because of clinical and methodological heterogeneity, results were synthesized narratively, and no meta-analysis was performed. Eighteen studies (9 prospective, 8 retrospective, 1 case series) including 542 patients were eligible. Eleven studies used Cs-131, six used I-125, and one used both. Prescribed doses ranged from 60 to 80 Gy, usually at a depth of 5 mm. One-year local control ranged from 83 to 100%. Symptomatic radionecrosis occurred in 4.6% of Cs-131 and 9% of I-125 implants; leptomeningeal disease rates were 1.6% and 12.5%, respectively. Postoperative S-IRT appears promising, but most studies were non-comparative and heterogeneous, so findings should be considered hypothesis-generating.