NCOG-67. Predictors of Mortality and Clinical Outcomes Following Surgical Resection of Multiple Brain Metastase

BACKGROUND Surgical resection in patients with MBM remains controversial due to their inherently poor prognosis. However, in carefully selected patients, surgery may offer symptom relief, improved local control, and quality-of-life benefits. This study aimed to identify independent predictors of mortality and outcomes in patients with multiple brain metastases (MBM) following surgical resection. METHODS Patients with ≥2 brain metastases who underwent surgical resection at a tertiary hospital from 2011–2019 were included. Primary outcomes were mortality and change in Clinical Frailty Scale (CFS). Secondary outcomes were recurrence and length of stay. Kaplan-Meier survival analysis was performed. Cox proportional-hazards and multivariable linear regression were used to identify independent predictors of outcomes. Covariates included age, sex, location of brain metastases, number of brain metastases, number resected, primary tumor, extracranial metastases, extracranial disease control, preoperative ECOG status, preoperative CFS, extent of resection, adjuvant radiotherapy, and adjuvant chemotherapy. RESULTS 68 patients (mean 58.9±11.6 years; 55.9% female) were included. Median overall survival was 8.81 months and median change in CFS was 1 (IQR 1–2). Median time to recurrence was 10.65 months. Median LOS was 16 days (IQR 10–40). Independent predictors of mortality included male sex (HR=7.15, 95% CI=2.41–21.1, p<0.001), number of brain metastases (HR=1.32, 95% CI=1.08–1.61, p=0.006), extracranial disease control (HR=0.380, 95% CI=0.170–0.849, p=0.018), adjuvant radiotherapy (HR=0.311, 95% CI=0.118–0.824, p=0.019), and adjuvant chemotherapy (HR=0.289, 95% CI=0.113–0.741, p=0.010). Independent predictors of change in CFS were preoperative ECOG (β=1.98, 95% CI=0.68–3.28, p=0.004) and adjuvant radiotherapy (β=-1.43, 95% CI=-2.59, -0.277, p=0.016). CONCLUSIONS Male sex, higher number of brain metastases, and uncontrolled extracranial disease predict increased mortality after surgery for multiple brain metastases, while preoperative functional status impacts postoperative frailty. Adjuvant radiotherapy and chemotherapy improve survival and reduce frailty progression. Incorporating these factors may improve risk stratification of surgical candidates for multiple brain metastases.