Surgical resection with postoperative stereotactic radiosurgery versus stereotactic radiosurgery alone for large (>3 cm) multiple brain metastases: a propensity score-matched analysis.

PURPOSE: While surgery plus stereotactic radiosurgery (SRS) is established for solitary brain metastases, its role in multiple brain metastases (MBM) remains unclear. This study compared survival in MBM patients undergoing resection of the largest tumor plus postoperative SRS versus SRS alone. METHODS: This retrospective study included adults with 2-4 MBM, a dominant lesion >3 cm, and Karnofsky Performance Status ≥70. We compared patients undergoing resection of the dominant lesion plus SRS against those receiving SRS alone. Propensity-score matching (PSM) balanced baseline characteristics. Overall survival (OS), progression-free survival (PFS), and prognostic factors were analyzed. RESULTS: Of 103 patients, 16 received surgery plus SRS and 87 received SRS alone. After PSM, groups were well-balanced (median largest diameter 41.7 vs. 38.4 mm, p=0.218). Surgery plus SRS significantly improved median OS (38.9 vs. 11.6 months, p=0.013) and PFS (14.3 vs. 4.7 months, p=0.048). Multivariable regression identified surgical resection (HR 0.33, 95% CI 0.15-0.71; p=0.004), lung-cancer primary (HR 0.58, 95% CI 0.35-0.97; p=0.037), and targeted/immunotherapy (HR 0.30, 95% CI 0.18-0.51; p<0.001) as favorable prognostic factors, whereas extracranial progression predicted worse survival (HR 2.21, 95% CI 1.32-3.71; p=0.002). CONCLUSION: For a highly selected group of MBM patients with good performance status and a dominant mass >3 cm, resecting the largest tumor followed by SRS may be associated with improved OS and PFS compared to SRS alone. Prospective studies are needed to validate these preliminary findings.