Removal of primary tumor improves survival in metastatic breast cancer. Does timing of surgery influence outcomes?

Background: Resection of intact primary tumor is controversial in metastatic breast cancer patients. The aim of this study is to review the impact of surgical resection of primary tumor on overall survival and to assess the role of timing of surgery on survival rates.

Methods: 208 patients with metastatic breast cancer diagnosed between 1982 and 2005 in the Hospital Clinico of Valencia (Spain) were analysed. Exclusion criteria were age >80, PS 3-4, Charlson score 3 or follow-up < 90 days. 123 of these underwent surgery and 85 did not. In order to assess the role of timing, the "surgery" cohort was divided into two sub-groups: "before" (n = 78) or "after" (n = 45) diagnosis of disseminated disease.

Results: In the surgery group, patients underwent mastectomy with axillary dissection (82.9%), without axillary dissection (8.9%) and conservative surgery (8.1%). After a median follow-up of 29.68 months, median OS in the "surgery" and the "non-surgery" groups were, 40.4 and 24.3 months. Removal of the primary tumor therefore had a significant positive impact on survival rates (p < 0.001). Benefits of surgery were observed mainly in patients with visceral disease (p = 0.005); no statistical differences were found in those with bone disease (p = 0.79). Univariate analysis for overall survival (OS) identified surgery, performance status, clinical T stage, hormone receptors and number and type of metastases as variables that impacted on survival. In the multivariate test, only resection of primary tumor and estrogen receptors maintained statistical significance, surgery having a protective effect with an HR 0.52 (95% CI 0.35-0.77). No differences in survival were found between the two sub-groups according to the timing of surgery: "before" vs "after"(p = 0.996).

Conclusions: Resection of primary tumor should be considered not only as a palliative or preventive strategy but also as an approach that possibly contributes to the control of the disease in selected patients.