Is function-based resection using intraoperative awake brain mapping feasible and safe for solitary brain metastases within eloquent areas?

To assess feasibility and safety of function-based resection under awake conditions for solitary brain metastasis patients. Retrospective, observational, single-institution case-control study (2014-2019). Inclusion criteria are adult patients, solitary brain metastasis, supratentorial location within eloquent areas, and function-based awake resection. Case matching (1:1) criteria between metastasis group and control group (high-grade gliomas) are sex, tumor location, tumor volume, preoperative Karnofsky Performance Status score, age, and educational level. Twenty patients were included. Intraoperatively, all patients were cooperative; no obstacles precluded the procedure from being performed. A positive functional mapping was achieved at both cortical and subcortical levels, allowing for a function-based resection in all patients. The case-matched analysis showed that intraoperative and postoperative events were similar, except for a shorter duration of the surgery (p<0.001) and of the awake phase (p<0.001) in the metastasis group. A total resection was performed in 18 cases (90%, including 10 supramarginal resections), and a partial resection was performed in two cases (10%). At three months postoperative months, none of the patients had worsening of their neurological condition or uncontrolled seizures, three patients had an improvement in their seizure control, and seven patients had a Karnofsky Performance Status score increase ≥10 points. Function-based resection under awake conditions preserving the brain connectivity is feasible and safe in the specific population of solitary brain metastasis patients and allows for high resection rates within eloquent brain areas while preserving the overall and neurological condition of the patients. Awake craniotomy should be considered to optimize outcomes in brain metastases in eloquent areas.