Survival benefit of a combined surgical approach in patients with metastatic breast cancer

Background We previously reported survival benefit of surgery in patients with stage IV breast cancer (BC); prospective trials yielded inconclusive results. Methods We sampled the National Cancer Database (2004-2016) for de novo stage IV BC patients undergoing both primary site resection and metastasectomy. A multivariate Cox-regression survival model investigated the overall survival (OS) of this surgical approach as compared to lumpectomy/mastectomy alone, metastasectomy alone, or no surgery. The Kaplan-Meier method was used to demonstrate the utility of surgery when metastasis were confined to 1 site stratifying by tissue type. Results A total of n = 55,125 patients were included. As compared to lumpectomy/mastectomy alone (43 months), lumpectomy/mastectomy + metastasectomy exhibited the best OS (50 months, p = 0.012), metastasectomy alone showed slightly worse OS (30 months, p < 0.0001), and no surgery had the worst OS (21 months, p < 0.0001). In metastasis confined to 1 site, superior OS with combined lumpectomy/mastectomy and metastasectomy versus lumpectomy/mastectomy alone was observed with liver (72.8 vs. 48.1 months, p < 0.001) or lung (49.2 vs. 36.8 months, p < 0.001) metastasis but not bone (52.2 vs. 49.9 months, p < 0.001) or brain (16.2 vs. 15.5 months, p < 0.001). Conclusion Patients with metastatic BC undergoing primary site resection and metastasectomy exhibited optimal OS, particularly when metastasis involved only the liver or lung.