Surgery for brain metastases—impact of the extent of resection

BACKGROUND: Surgical resection of brain metastases improves symptoms and survival in selected patients. The benefit of gross total resection is disputed, as most patients are believed to succumb from their non-CNS tumor burden. We investigated the association between overall survival and residual tumor after surgery for single brain metastases. METHODS: We reviewed adults who underwent surgery for a single brain metastasis at a regional referral center (2011–2018). Gross total resection was defined as no visible residual tumor on cerebral MRI 12–48 h postoperatively. RESULTS: We included 373 patients. The most common primary tumors were lung cancer (36%) and melanoma (24%). We identified gross total resection in 238 patients (64%). Median overall survival was 11.0 months, 8.0 (6.2–9.8) months for patients with subtotal resection and 13.0 (9.7–16.3) months for patients with gross total resection. In a multivariate regression analysis including preoperative prognostic factors, gross total resection was associated with longer overall survival (HR: 0.66, p = 0.003). Postoperative radiotherapy administered within 6 weeks did not significantly alter the hazard ratio estimates for grade of resection. CONCLUSIONS: Our study suggests improved survival with gross total resection compared to subtotal resection. The importance of extent of resection in surgery for brain metastases should not be discarded.