[Investigation of Patients with Stage Ⅳ Breast Cancer Who Underwent Primary Tumor Resection].

We investigated whether primary tumor resection performed at our department for the purpose of local control affects the disease progression of Stage Ⅳ breast cancer. Fifteen patients who underwent primary tumor resection between 2009 and 2017 were investigated. The median age at the time of surgery was 63 years. There were two postoperative deaths(1 at<1 year postoperatively and 1 at<2 years postoperatively). The median postoperative stable disease(SD)period was 11 months overall and was 12 months or longer in 7 patients. SD was attained by all patients with the first drug treatment after primary tumor resection. Patients who tended to have a longer postoperative SD period did not receive preoperative drug treatment, were luminal HER2-positive, and had one metastatic organ. Regardless of surgery timing and reason, there were no cases of rapid postoperative disease progression. In all patients, postoperative local control was satisfactory, and continuation of medical treatment was feasible for distant metastatic tumors. These data signify that primary tumor resection can be considered to treat Stage Ⅳ breast cancer for the purpose of local control.