Effect of primary tumor resection on overall survival in patients with stage IV breast cancer

We aimed to evaluate the effect of primary tumor resection on overall survival in stage IV breast cancer patients. In total, 284 breast cancer patients presenting with breast cancer at stage IV at initial diagnosis, between 2001 and 2014, were enrolled in the study. Patients were divided into two groups based on surgical resection of the primary tumor. Overall survival (OS) between the two groups was analyzed. Patients in the surgery group (n = 92) had smaller tumors than those in the no-surgery group (n = 192, T0-1:17.7% vs 34.8%, P < 0.001). The surgery group more often had negative nodal status (5.7% vs 33.7%, P < 0.001). Multiple metastatic organ sites were more common in the no-surgery group than in the surgery group (55.7% vs 15.2%, P < 0.001). The surgery group showed a better OS than the no-surgery group (P = 0.01). Multivariate analysis showed that surgical resection of primary tumors tended to be associated with improved OS (HR = 0.67, P = 0.055). T stage, ER, HER2 and metastatic organ sites were independent prognostic factors for OS in multivariate analysis. Surgical resection of the primary tumor may be a treatment option for patients with stage IV disease and may not have a negative effect on overall survival.