Breast surgery in stage IV breast cancer: impact of staging and patient selection on overall survival

Purpose Retrospective analyses suggest patients with stage IV breast cancer who undergo breast surgery have improved survival. We sought to determine whether surgery and other clinical and staging factors affected overall survival. Methods We performed a review of our prospectively maintained database of patients who presented with stage IV breast cancer between 1998 and 2005. We compared survival between women who received therapeutic surgery to the breast (S) versus those who did not (NS). Results Of the 147 women who presented with stage IV breast carcinoma, 61 (41%) underwent mastectomy or lumpectomy. Median overall survival unadjusted was 3.52 years for S versus 2.36 years for NS (P = 0.093). ER and Her2neu status were positive predictors of survival (HR: 0.191 and 0.285 P < 0.0001); CNS and liver metastases were adverse predictors (HR: 2.05 and 1.59 P = 0.015 P = 0.059). On multivariate survival was significantly superior in the surgery group (HR: 0.47 P = 0.003 mean 4.13 years versus 2.36 years). In those undergoing surgery, 36 women were diagnosed with metastatic disease postoperatively and 25 preoperatively. These groups had median survival of 4.0 years and 2.4 years, respectively, comparable to those in the NS group (2.36 years, (P = 0.18). Conclusions Breast surgery is associated with improved survival in stage IV breast cancer. However, in our experience, this benefit is only realized among patients operated on before diagnosis of metastatic disease and is likely a consequence of stage migration bias. While some women may warrant palliative surgery to the breast, it is unclear that such surgery otherwise improves clinical outcomes.