Locoregional treatment of the primary tumor may improve overall survival and cancer-specific survival in breast cancer patients with bone metastases

Abstract Aims: we sought to analyze data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program to conduct an epidemiologic study of the potential effect of surgery on survival in breast cancer patients with bone metastases. Methods: Included in the analyses were histologically confirmed AJCC M1 breast cancer with bone metastasis who were diagnosed from January 2010 to December 2011. These patients were grouped according to whether or not they have undergone mastectomy. To account for differences in baseline characteristics, a propensity score was estimated to optimally adjust the data for the bias between the two groups. Results: From a total of 1180 breast cancer patients with bone metastasis, 508 patients underwent mastectomy and 672 did not undergo mastectomy. The 3-, and 5-year overall survival rates for patients who underwent palliative mastectomy were 67.2%, and 45.8% compared with 49.5%, and 27.9% for patients who did not undergo mastectomy. The 3-, and 5-year cancer-specific survival rates for patients who underwent palliative mastectomy were 69.1%, and 49.2% compared with 52.4%, and 30.7% for patients who did not undergo mastectomy. Using the weights and strata obtained by the propensity score matching procedure, The 3-, and 5-year overall survival rates for patients who underwent palliative mastectomy were 68.1%, and 45.6% compared with 48.8%, and 28.7% for patients who did not undergo mastectomy；The 3-, and 5-year cancer-specific survival rates for patients who underwent palliative mastectomy were 70.2%, and 49.7% compared with 53.3%, and 31.9% for patients who did not undergo mastectomy. Conclusions: Locoregional treatment was shown to be independently associated with improvement in survival in IV breast cancer patients with bone metastases. Therefore, surgical management for the primary tumor could be considered more actively in selected patients with stage IV breast cancer.