Effect of Surgery at Primary and Metastatic Sites in Patients With Stage IV Breast Cancer

There is no clear evidence of a survival benefit of resection of the primary tumor, or distant site resection (metastasectomy) in patients with stage IV breast cancer.This retrospective analysis of stage IV breast cancer using the National Cancer Database. To evaluate variables associated with surgery at the primary site, we used univariate analyses followed by multivariate logistic regression. Consequently, we evaluated the impact of lumpectomy, mastectomy or metastasectomy on survival by conducting multivariate Cox regression survival analyses on the following groups: all stage IV patients; a subset of those with only one metastatic site; and another subset with metastasis to multiple distant sites.A total of 54,871 stage IV breast cancer patients were included in this analysis. Variables associated with the use of surgery at the primary were: age, race, Charlson/Deyo score, insurance and facility type, involved breast quadrant, receptor status, N stage, extent of metastasis, and year of diagnosis. Survival analysis showed that both lumpectomy (median overall survival [OS], 45 months) and mastectomy (median OS, 44 months) were associated with better OS compared to no surgery (median OS, 22 months). The statistical effect was larger in the subgroup with metastasis to one site, but still significant in the subgroup with multiple metastatic sites. Distant site resection also yielded a survival benefit.In patients with metastasis to only one site, metastasectomy was associated with better OS when that site was the liver, lung, or brain.