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, has more than tripled from 2002 to 2012 despite evidence suggesting no survival benefit over breast conservation, according to a new study from Brigham and Women's Hospital (BWH) published in Annals of Surgery on March 11, 2016.
Researchers note that while CPM may have a survival benefit for patients that 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 while contributing to 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 operative 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 unilateral stage-one to stage-three breast cancer diagnosis and followed them over a period of 8.25 years, from 1998-2012. Patients undergoing breast conserving surgery, unilateral mastectomy and CPM were compared and of the 496,488 women diagnosed with unilateral invasive breast cancer, 59.6 percent underwent breast-conserving surgery, 33.4 percent underwent unilateral mastectomy and seven 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. Relative to patients undergoing unilateral mastectomy or breast-conserving surgery, patients undergoing CPM were more likely to be Caucasian.
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, researchers show that rates of reconstruction in CPM patients increased from 35.3 per cent to 55.4 per cent 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, also 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 optimally counsel women about surgical options, address anxieties, discuss individual preferences and ensure peace of mind related to a patient's surgical choice," Golshan said.
Researchers note that further research on how to optimally counsel women about surgical options is warranted.
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