Surgery of the Primary Tumor in Metastatic Breast Cancer: Closing the Barn Door After the Horse Has Bolted?

Abstract

Traditionally, metastatic breast cancer is considered to be incurable, and the goals of treatment are the prolongation of life and the palliation or prevention of symptoms. Within this context, it is not surprising that local therapy is not routinely recommended for patients presenting with stage IV disease and intact primary tumors. Surgery is reserved for patients who develop complications such as bleeding, ulceration, and infection at the primary tumor site, a type of surgery that historically has been described as “toilette” mastectomy. In this issue of the Journal of Clinical Oncology, Rapiti et al 1 present the results of a retrospective, population-based study of the impact of surgical therapy of the primary tumor on survival outcomes in 300 women with metastatic disease at the time of the initial diagnosis of breast cancer. The authors observed that women having surgery of the primary tumor had a 50% reduction in breast cancer mortality compared with women who did not undergo surgery, the survival benefit was limited to women with tumor-free margins of resection, and a significant survival benefit for axillary surgery was not observed. These results are strikingly similar to those reported by Khan et al 2 in a retrospective study of 16,023 patients presenting with stage IV disease at initial breast cancer diagnosis. In the work of Khan, surgery of the primary tumor was associated with a 39% reduction in the risk of death, with a 3-year survival of 35% for patients excised to negative margins, 26% for those with positive margins, and 17.3% for those not having surgery (P .0001). Again, axillary dissection was not found to contribute significantly to survival. Both Rapiti et al 1 and Khan et al 2 adjusted for factors such as number of metastatic sites, location of metastases (visceral v bone and soft tissue), and type of systemic therapy that might have differed between patients who had surgical treatment and those who did not. However, both studies concluded that unrecognized selection bias may have accounted for the observed benefit of surgery, and only a large, prospective randomized trial could determine reliably whether surgery of the primary tumor prolongs survival in the patient presenting with metastatic breast cancer. The merits of prospective, randomized trials are obvious, but