Does aggressive local therapy improve survival in metastatic breast cancer?

Background. Women with metastatic breast cancer and an intact primary tumor are currently treated with systemic therapy. Local therapy of the primary tumor is considered irrelevant to the outcome, and is recommended only for palliation of symptoms. Methods. We have examined the use of local therapy, and its impact on survival in patients presenting with stage IV breast cancer at initial diagnosis, who were reported to the National Cancer Data Base (NCDB) between 1990 and 1993. Results. A total of 16,023 patients with stage IV disease were identified in the NCDB during this period, of whom 6861 (42.8%) received either no operation or a variety of diagnostic or palliative procedures, and 9162 (57.2%) underwent partial (3513) or total (5649) mastectomy. The presence of free surgical margins was associated with an improvement in 3-year survival in partial or total mastectomy groups (26% vs 35%, respectively). A multivariate proportional hazards model identified the number of metastatic sites, the type of metastatic burden, and the extent of resection of the primary tumor as significant independent prognostic covariates. Women treated with surgical resection with free margins, when compared with those not surgically treated, had superior prognosis, with a hazard ratio of 0.61 (95% confidence interval 0.58,0.65). Conclusions. These data suggest that the role of local therapy in women with stage IV breast cancer needs to be re-evaluated, and local therapy plus systemic therapy should be compared with systemic therapy alone in a randomized trial.