The use of contralateral prophylactic mastectomy (CPM)—the surgical removal of a breast unaffected by cancer as part of the course of treatment for breast cancer—more than tripled from 2002 to 2012. However, according to a new BWH study, there has been no evidence of a survival benefit for patients who receive CPM compared to patients who receive breast-conserving surgery, which removes part of the breast tissue but not the entire breast.
Researchers note that while CPM may have a survival benefit for patients who are at high risk of developing breast cancer, such as those with a genetic mutation, the majority of women undergoing CPM are at low risk for developing breast cancer in the unaffected breast. Data show that women who are diagnosed with cancer in one breast are increasingly unlikely to be diagnosed with cancer in the other breast.
“Our analysis highlights the sustained, sharp rise in popularity of CPM and the mounting evidence that this more extensive surgery offers no significant survival benefit to women with a first diagnosis of breast cancer,” said senior author Mehra Golshan, MD, distinguished chair in Surgical Oncology at BWH. “Patients and caregivers should weigh the expected benefits with the potential risks of CPM, including prolonged recovery time, increased risk of complications, cost, the possible need for repeat surgery and effects on self-image.”
Researchers analyzed data from a group of nearly 500,000 women with a stage-one to stage-three breast cancer diagnosis in one breast and followed them from 1998 to 2012. Patients undergoing breast-conserving surgery, unilateral mastectomy—the removal of one breast—and CPM were compared. Nearly 60 percent underwent breast-conserving surgery, 33.4 percent underwent unilateral mastectomy and 7 percent underwent CPM. Overall, the proportion of women undergoing CPM increased from 3.9 percent in 2002 to 12.7 percent in 2012. When compared with breast-conserving therapy, no significant improvement in survival was found for women undergoing CPM.
Importantly, CPM may be indicated for women with BRCA1/2 mutations, a strong family history of breast or ovarian cancer or a personal history of mantle field radiation during childhood. A significant number of younger women are actively choosing CPM over conservative surgery, but only about a third of women who opt for CPM have one or more of these risk factors. Surveys of women suggest that a desire to minimize breast asymmetry and improve overall appearance through increasingly available and expanding reconstructive techniques may influence a decision to undergo CPM. Specifically, research shows that rates of reconstruction in CPM patients increased from 35.3 percent to 55.4 percent during the study period.
“Women with unilateral breast cancer undergoing CPM continue to report a desire to extend life as one of the most important factors leading to their surgical decision,” said Golshan, who is also the medical director of International Oncology Programs at Dana-Farber/Brigham and Women’s Cancer Center. “Understanding why women choose to undergo CPM may create an opportunity for health care providers to counsel women about surgical options, address anxieties, discuss individual preferences and ensure peace of mind related to a patient’s surgical choice.”