Surgical resection of the primary tumor is associated with increased long-term survival in patients with stage IV breast cancer after controlling for site of metastasis

Background: The benefit of surgical resection in patients presenting with metastatic breast cancer is not established. We hypothesized that surgical excision of primary tumors in patients with stage IV breast cancer would be associated with increased survival. Methods: Chart review identified 409 patients with stage IV breast cancer treated from 1996 to 2005; 187 received surgical excision of their primary tumor and 222 did not. One hundred and two patients had bone-only metastases, 281 had metastases to other organs ± bone, and 26 had no metastases recorded. Patient characteristics were compared between groups using the chi-squared test. Cox regression models were used to calculate adjusted hazard ratios (aHR). The log-rank test compared the differences in survival between patients who did or did not undergo surgical resection. Results: Mean age at diagnosis of all 409 patients was 57.8 ± 15.0 years. After controlling for age, comorbidity, tumor grade, histology, and sites of metastasis, patients who underwent surgical resection had longer median survival when compared with patients who did not undergo surgical resection (31.9 vs. 15.4 months, p < 0.0001; aHR 0.53 [95% CI 0.42-0.67]). Conclusions: Surgical excision of the primary breast tumor was associated with significantly longer survival in this cohort of stage IV breast cancer patients, even after controlling for other factors associated with survival. Randomized clinical trials are needed to validate these findings.