The current role of surgery for single brain metastases

Surgery for singular brain metastases (BM) aims to improve survival by providing control of CNS disease. This concept may need to be refined against the background of recent advances in medical and radiation oncology. In particular there is a debate about the prognostic role of residual tumor.

Does extent of resection influence overall- and cerebral progression-free-survival as well as functional outcome?

This retrospective series comprised 202 patients with single BM who underwent surgery 2015-2023. All patients underwent pre- and postoperative MR imaging.

Surgical indications included a tumor too large for radiosurgery (≥15.0 cm³; 42.5 %) and tissue acquisition for molecular analyses for potential therapeutic targets (21.8 %). Extent of resection was categorized as incomplete (8.4 %), questionably complete (22.3 %), and complete (69.3 %). Median residual tumor volume was only 0.12 cm³ (IQR 0.04-0.35). Complete resection was not correlated with better overall (OS) or CNS progression free survival. Complication rates and postoperative KPS did not vary significantly with resection category. Postoperative MRI revealed two cases with unilateral sigmoid sinus thrombosis in asymptomatic patients (cf. 11/16 [69.0 %] complications requiring treatment in symptomatic patients). We recorded 6.2 % major (CTCAE III-V) surgical, 5.3 % neurological, and 7.2 % medical complications. Postoperative treatment and major complications were prominent prognostic factors for OS.

Small tumor remnants may have limited impact on survival. In the era of targeted therapies tissue acquisition for molecular analysis is an increasingly important indication for BM surgery.