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February 10, 2021

Bilateral Mastectomy in Women With Unilateral Breast Cancer: A Review

Author Affiliations
  • 1Women’s College Research Institute, Women’s College Hospital, Toronto, Ontario, Canada
  • 2Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Ontario, Canada
  • 3Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
  • 4Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
JAMA Surg. 2021;156(6):569-576. doi:10.1001/jamasurg.2020.6664

Importance  Rates of bilateral mastectomy continue to increase in average-risk women with unilateral in situ and invasive breast cancer. Contralateral prophylactic mastectomy rates increased from 5% to 12% of all operations for breast cancer in the US from 2004 to 2012. Among women having mastectomy, rates of contralateral prophylactic mastectomy have increased from less than 2% in 1998 to 30% in 2012.

Observations  The increased use of breast magnetic resonance imaging and genetic testing has marginally increased the number of candidates for bilateral mastectomy. Most bilateral mastectomies are performed on women who are at no special risk for contralateral cancer. The true risk of contralateral breast cancer is not associated with the decision for contralateral prophylactic mastectomy; rather, the clinical factors associated with the probability of distant recurrence are associated with bilateral mastectomy. Several changes in society and health care delivery appear to act concurrently and synergistically. First, the anxiety engendered by a fear of cancer recurrence is focused on the contralateral cancer because this is most easily conceptualized and provides a ready target that can be acted upon. Second, the modern woman with breast cancer is supported by the surgeon and the social community of breast cancer survivors. Surgeons want to respect patient autonomy, despite guidelines discouraging bilateral mastectomy, and most women have their expenses covered by a third-party payer. Satisfaction with the results is high, but the association with improved psychosocial well-being remains to be fully understood.

Conclusions and Relevance  Reducing the use of medically unnecessary contralateral prophylactic mastectomy in women with nonhereditary, unilateral breast cancer requires a social change that addresses patient-, physician-, cultural-, and systems-level enabling factors. Such a transformation begins with educating clinicians and patients. The concerns of women who want preventive contralateral mastectomy must be explored, and women need to be informed of the anticipated benefits (or lack thereof) and risks. Areas requiring further study are considered.

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    1 Comment for this article
    Contralateral Prophylactic Mastectomy Requires Complex Shared Decision-Making
    Julia Cron, Assistant Professor | Yale School of Medicine
    Lim et al accurately dissect the complexity of surgical options for breast cancer. Medically unnecessary procedures should not occur; thankfully, the days of radical mastectomy for most breast cancer cases have passed. However, I caution against the authors’ description of contralateral prophylactic mastectomy (CPM) as potentially “medically unnecessary,” as it undermines the nuances of shared decision-making in breast cancer care.

    Although there is no improved survival benefit with CPM, the authors note a wide range in the cumulative risk of contralateral breast cancer (CBC) based on patient characteristics, and a risk reduction of CBC by 95%
    with CPM. Despite risk predictors having “modest accuracy,” risk reduction and cumulative risk of CBC are important considerations for patients.

    The psychologic impact of breast cancer should not be underestimated. The authors note “as clinicians and researchers, we tend to focus on survival … whereas the patient prioritizes anxiety, fear, and quality of life.” Although the evidence differs with respect to CPM’s impact on cancer-related fear and anxiety, physicians should prioritize these individual patient concerns.

    Additionally, the role of reconstruction should be emphasized. Although the authors note there is no consensus among plastic surgeons which procedure achieves better cosmesis, they note evidence for increased satisfaction among women with any reconstruction. The question of satisfaction with unilateral vs. bilateral mastectomy with reconstruction remains unanswered. Additionally, the risks of reconstruction should be clarified. The authors note doubling of the complication risk in CPM; however, this is based on a 2004 study in which more than 50% of patients underwent TRAM flaps. Outcomes based on different methods of reconstruction deserve further investigation.

    Importantly, the authors note the challenge for patients and physicians to “deconstruct” the risks of ipsilateral recurrence, distant recurrence, and contralateral cancer. It is distressing that surgeons agree many women choose CPM because of a falsely increased perceived risk of contralateral cancer and death, and it is a disservice to women to defer simply to autonomy without “properly disentangling” these risks with potential psychologic and cosmetic benefits.

    Many questions remain. However, before CPM is deemed “medically unnecessary,” remaining questions should be clarified. Meanwhile, shared decision-making which is honest, data-driven, and patient-focused should be emphasized. This is challenging and nuanced, particularly without clear data. However, as a Stage 2B breast cancer survivor who chose CPM, I appreciated the frank discussions with my physicians about the risks and benefits of my treatment options, ultimately helping me make my decision.