Hormone receptor status may impact the survival benefit of surgery in stage iv breast cancer: a population-based study.

INTRODUCTION: The role of surgery in stage IV breast cancer is controversial. We used the Surveillance, Epidemiology, and End Results database to explore the impact of surgery on the survival of patients with stage IV breast cancer.

METHODS: In total, 10,441 eligible stage IV breast cancer patients from 2004 to 2008 were included. They were divided into four groups as follows: R0 group (patients who underwent primary site and distant metastatic site resection), primary site resection group, metastases resection group, and no resection group.

RESULTS: The four groups achieved a median survival time (MST) of 51, 43, 31 and 21 months, respectively, P < 0.001. The Cox proportional hazards model showed that the R0 group, primary resection group and metastases resection group had a good survival benefit, with hazard ratios of 0.558 (95% CI, 0.471-0.661), 0.566 (95% CI, 0.557-0.625) and 0.782 (95% CI, 0.693-0.883), respectively. In the hormone receptor (HR)-positive population, the R0 group (MST = 66 m, 5-year OS = 54.1%) gained an additional survival benefit compared with the primary resection group (MST = 52 m; 5-year OS = 44.9%; P < 0.001). The metastases resection group (MST = 38 m; 5-year OS = 31.7%) survived longer than the no resection group (MST = 28 m; 5-year OS = 22.0%; P < 0.001). In the HR-negative population, the R0 group and primary resection group had a similar survival (P = 0.691), and the metastases resection group had a similar outcome to that of the no resection group (P = 0.526).

CONCLUSION: Patients who underwent surgery for stage IV breast cancer showed better overall survival than the no resection group. Cytoreductive surgery could provide a survival benefit in HR+ stage IV breast cancer; however, in the HR- population, extreme caution should be exercised when considering surgery.