Survival Benefit of Surgical Removal of Primary Tumor in Patients With Stage IV Breast Cancer

Background: Several studies have suggested that primary tumor removal improved overall survival for patients with stage IV breast cancer. However, the survival benefit of local treatment remains controversial. The purpose of the present study was to determine whether surgical removal of the primary tumor provides survival benefits to patients with stage IV breast cancer.

Patients and methods: We retrospectively reviewed the medical records of 155 patients with an initial diagnosis of stage IV breast cancer at Seoul National University Bundang Hospital from 2003 to 2014. Kaplan-Meier analysis was used to estimate the median survival. The log-rank test was used to compare differences in patient and tumor characteristics. Multivariate Cox regression analysis for survival was used, controlling for potential confounding variables.

Results: Of 155 patients with stage IV breast cancer, 95 (61%) underwent surgical removal of the primary tumor. The median follow-up period was 59 months (95% confidence interval [CI], 45-73 months). The median survival was longer for the patients with a better response to chemotherapy (70 vs. 47 months; P = .010) and for those who had undergone surgery (118 vs. 28 months; P < .001) than for those who without a better chemotherapy response or surgery. The median survival of the patients who received radiotherapy was better than that of the patients who did not (65 vs. 39 months; P = .004). Patients with luminal A cancer had a median survival of 118 months, the longest compared with those with other subtypes (P = .001). In addition, patients with distant metastasis at a single site had a longer median survival than did those with multiple metastatic sites. The multivariate Cox regression analysis revealed that fewer distant metastases, surgery of the primary tumor, a better response to chemotherapy, and luminal A subtype were significant independent predictors of survival.

Conclusion: Our results showed that primary tumor removal was independently associated with improvement in survival. Therefore, surgical management for the primary tumor could be considered more actively in patients with stage IV breast cancer.