In recent years, there has been significant controversy surrounding the use of contralateral prophylactic mastectomy (CPM) among women with newly diagnosed unilateral breast cancer. “Women in the United States are increasingly opting for mastectomy and CPM, even among those who are candidates for breast conservation,” says Judy C. Boughey, MD.
To address this issue, the American Society of Breast Surgeons (ASBrS) recently convened an expert panel to develop a consensus statement on CPM. The document outlines the available data on the impact of CPM on cancer and non-cancer outcomes, including risks of CPM and when CPM should be considered or discouraged (Table). The consensus statement was published in Annals of Surgical Oncology.
“The option of removing the contralateral breast is often discussed for women who elect for or require mastectomy to manage their index breast cancer,” says Dr. Boughey, who chaired the ASBrS expert panel that developed the document. “The consensus statement was developed to guide patient and physician discussions and ensure patients are making informed treatment decisions.”
Multiple factors need to be considered when deciding whether to pursue surgical removal of the healthy (“normal”) contralateral breast, including family history, patient age, comorbidities, and tumor prognosis. These considerations must also take into account the initial surgical plan as well as the possible use of systemic therapy and radiotherapy. Furthermore, the ASBrS recommends including patients’ values, goals, and preferences during the shared decision-making process when discussing CPM.
During surgical consultations, clinicians should discuss in detail local treatment options, the risk of developing a contralateral breast cancer (CBC), and distant cancer recurrence. “Patients should be informed of the pros and cons of CPM and receive a clear recommendation either for or against CPM,” Dr. Boughey says. She adds that it is important for candidates to recognize that CPM is never an emergency or mandatory, even for patients at the highest risk of CBC; close surveillance is a reasonable alternative to prophylactic surgery.
Breast Conservation or Mastectomy
The ASBrS panel recommends advocating for breast conservation for all appropriately eligible patients and considering neoadjuvant systemic therapy and/or oncoplastic approaches to facilitate breast conservation whenever possible. Breast conservation has been shown to be equivalent to mastectomy in terms of survival outcome and has been the preferred treatment for early-stage breast cancer since the National Cancer Institute issued guidelines back in 1991. Increasing the use of breast conservation can decrease CPM rates. Data show that complication rates are lower with breast-conserving surgery and adjuvant radiation than with mastectomy and reconstruction.
CPM & Cancer Outcomes
According to the guidelines, the risk of CBC for average-risk women with breast cancer is 2% to 6 % over the next 10 years. This means that these women have a 94% to 98% chance of not getting cancer in their opposite breast over the next 10 years or more. CBC risk is higher for women who are diagnosed at a young age, those with a strong family history, and BRCA carriers. “While there is strong evidence that CPM can help reduce the relative risk of cancer in the contralateral breast, this risk is not completely eliminated with CPM,” Dr. Boughey says. The absolute risk of developing cancer on that side after CPM ranges widely. CPM does not appear to be associated with a survival benefit, with the possible lone exception being patients who are BRCA carriers.
Importantly, patients should be informed that CPM doubles the risk of surgical complications. This increased risk is prevalent regardless of whether reconstruction is performed or not, and complications occur almost equally on the affected and prophylactic sides. Potential comorbidities—including cardiac or pulmonary comorbidities, obesity, diabetes, smoking, and use of steroids or anticoagulants—can also increase the likelihood of complications from CPM and should be considered when evaluating treatment options. Surgical complications can also delay the onset of adjuvant systemic therapy and/or radiotherapy.
The ASBrS recommendations note that symmetry is a significant driver for women to select CPM. “Bilateral reconstruction may provide better cosmetic outcome, but clinicians need to talk about the other side effects and risks that are associated with CPM, including sensation loss and possible loss of the nipple areolar complex, depending on the type of mastectomy,” says Dr. Boughey. Consultations with patients should involve a detailed discussion about what reconstructive procedures involve, the recovery time, the need for additional operations, and the risks associated with these procedures. Women should also be informed that symmetrization procedures are available that do not require mastectomy. These procedures can provide a symmetrical result with potentially fewer surgical and wound complications while also preserving sensation.
The guidelines note that about 10% of women regret their decision to undergo CPM. “Ultimately, the purpose of ASBrS statement is to encourage shared decision making,” Dr. Boughey says. “CPM can have a negative impact on physical, emotional, and sexual well-being, and each patient will have different views based on their own unique preferences. Our mission as clinicians is to educate patients thoroughly so that there are no regrets after deciding on a treatment.”
Readings & Resources (click to view)
Boughey JC, Attai DJ, Chen SL, et al. Contralateral prophylactic mastectomy (CPM) consensus statement from the American Society of Breast Surgeons: data on CPM outcomes and risks. Ann Surg Oncol. 2016;23:3106-3111. Available at: http://link.springer.com/article/10.1245%2Fs10434-016-5443-5.
Boughey JC, Hoskin TL, Hartmann LC, et al. Impact of reconstruction and reoperation on long-term patient-reported satisfaction after contralateral prophylactic mastectomy. Ann Surg Oncol. 2015;22:401-408.
Brown D, Shao S, Jatoi I, Shriver CD, Zhu K. Trends in use of contralateral prophylactic mastectomy by racial/ethnic group and ER/PR status among patients with breast cancer: a SEER population-based study. Cancer Epidemiol. 2016;42:24-31.