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

Bilani, Nadeem; Elson, Leah; Liang, Hong; Elimimian, Elizabeth Blessing; Nahleh, Zeina

BACKGROUND There is no clear evidence that resection of the primary tumor, or distant site resection ('metastasectomy'), yields a survival benefit in patients with stage IV breast cancer (BC). METHODS We performed a retrospective analysis of patients with metastatic BC using the National Cancer Database. To evaluate variables associated with the use of surgery at the primary site, we first used univariate tests (ie, chi-squared or Wilcoxon rank-sum tests). Subsequently, we included significant predictors in a multivariate logistic regression model. We also evaluated the impact of lumpectomy, mastectomy, or metastasectomy on overall survival (OS) by conducting multivariate Cox regression analyses on the following 3 groups: (1) all patients with stage IV disease; (2) a subset of patients with a single metastatic site; and (3) another subset of patients with metastasis to multiple distant sites. RESULTS A total of 54,871 patients with stage IV BC were included in this analysis. Variables associated with the use of surgery at the primary were: age, race, Charlson/Deyo comorbidity score, insurance and facility type, involved breast quadrant, receptor status, American Joint Committee on Cancer clinical N-staging, extent of metastasis, and year of diagnosis. Survival analysis showed that both lumpectomy (median 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. CONCLUSION This large retrospective study has shown potential utility of a surgical approach in metastatic breast cancer. More research, particularly with prospective trials assessing the combined benefit of primary and secondary site resection, is needed to corroborate these data.