Contralateral prophylactic mastectomy is the surgical removal of the healthy breast in addition to the breast with cancer. The procedure is considered overused since the majority of studies have found a limited survival benefit for most women who undergo it. However, there are some breast cancer patients for whom it appears to make sense. Now a new study has reported that a contralateral prophylactic mastectomy might provide a survival benefit for women with hormone receptor negative disease (which includes triple negative breast cancer).
Contralateral prophylactic mastectomy can make sense for some women
Although each decision must be made based on individual patient characteristics, a contralateral prophylactic mastectomy might improve survival among very young women (under 35), BRCA mutation carriers, women with in situ disease (DCIS or LCIS) or very dense breasts who also have a family history of breast cancer, and women with inflammatory breast cancer. In addition, women with extensive multicentric disease or whose tumors were not visible (on mammograms) until they reached a size over 2 cm might be appropriate candidates for contralateral prophylactic mastectomy.
However, a number of women who do not fall into any of these categories are choosing to have bilateral mastectomies when only one breast has cancer. The logic behind such decisions is that the risk factors that led to breast cancer in one breast are probably also present in the other breast. Some women may also want to avoid the continuing breast cancer surveillance and anxiety associated with leaving the other breast in place. Studies to date are fairly consistent that most such women do not actually benefit from the additional surgery, assuming both breasts are carefully evaluated for disease. However, it is clear that more data is needed.
Latest research finds benefit of removal of disease-free breast for ER-/PR- disease
The study referenced at the beginning of this news article provides additional evidence concerning which women with early-stage breast cancer might benefit from contralateral prophylactic mastectomy. The study included 3,889 women with stage I to III breast cancer who were treated at the MD Anderson Cancer Center in Texas between 1997 and 2009.
The women were followed for a median of 4.5 years. As part of the analysis, women who underwent contralateral prophylactic mastectomy were carefully matched to women who did not, resulting in a total of 497 matched pairs. All results were adjusted for known breast cancer prognostic factors. In addition, the authors used a propensity scoring technique designed to reduce the selection bias typically caused by the nonrandom assignment of participants in observational studies.
Contralateral prophylactic mastectomy was found to be associated with a 25% lower risk of breast cancer recurrence and 26% reduced risk of death (from any cause) for the study group overall. The improved relapse-free survival was seen primarily in women with hormone receptor negative (ER-/PR-) tumors. Women with hormone receptor negative disease experienced a significant 40% reduction in risk of breast cancer recurrence whereas those with hormone receptor positive tumors saw a 20% reduction in risk that was not statistically significant. An improvement in breast cancer-free survival was also observed in the matched pair analysis for ER-/PR- women who underwent contralateral prophylactic mastectomy.
The authors conclude that contralateral prophylactic mastectomy is associated with better breast cancer-free survival for some women with ER-/PR- breast cancer. A more personalized approach to treatment decisions about contralateral prophylactic mastectomy requires identification of characteristics of patients most likely to benefit from the procedure.