Mastectomy is unnecessary in many women with stage IV breast cancer—and in fact may even facilitate the spread of the disease, according to the results of a study presented at the 2013 San Antonio Breast Cancer Symposium.
Mastectomy—surgical removal of the entire breast—is considered a loco-regional treatment and has long been considered standard therapy for stage IV (metastatic) breast cancer. However, some researchers have speculated that it does not improve overall survival and should not be considered a routine practice.
Researchers from India conducted a study that included 350 patients with metastatic breast cancer. All of the women had objective tumor response after 6 cycles of anthracycline based chemotherapy and were stratified by metastatic site, number of metastases, and hormone receptor status. The patients were randomly assigned to one of two treatment arms: Loco-regional treatment (LRT), which included mastectomy, complete axillary dissection, plus radiation therapy; or no loco-regional treatment (No-LRT). For disease progression, women received appropriate systemic treatment.
After a median follow-up of 17 months, median overall survival was 20.5 months for the non-surgical group and 18.8 months for the surgical group. Two-year overall survival was 43.3 percent in the non-surgical group and 40.8 percent in the surgical group. After adjusting for age, ER status, HER2 receptor status, site of metastases and number of metastatic lesions, there was no significant difference in overall survival between the two groups.
Interestingly, loco-regional treatment was associated with better local progression-free survival, but distant progression-free survival was worse in this group—leading the researchers to hypothesize that removal of the primary tumor might be enabling the disease to spread. In fact, the cited a decades-old animal study in which removal of a primary tumor appeared to release a growth factor that fostered the growth of distant tumors.
The researchers concluded that loco-regional treatment did not provide a survival benefit in women diagnosed with metastatic breast cancer who have responded to first-line chemotherapy. The suggest that surgery should be reserved as an option for palliative treatment.
Badwe R, Parmar V, Hawaldar R, et al: Surgical removal of primary tumor and axillary lymph nodes in women metastatic breast cancer at first presentation: A randomized controlled trial. 2013 San Antonio Breast Cancer Symposium. Abstract S2-02. Presented December 11, 2013.