Should the use of contralateral prophylactic mastectomy be increasing as it is?

Abstract

Recent studies have shown a dramatic increase in the use of contralateral prophylactic mastectomy (CPM). The choice of surgical procedure is primarily influenced by the recommendations of physicians and surgeons. As smaller breast cancers are detected by improved breast screening, and larger breast cancers are reduced in size by neo-adjuvant chemo- and endocrine therapy, breast conservation therapy (BCT) has been applicable to more women. No one would advocate CPM with the breast primary was to be treated by BCT. This makes the more than doubling of the rate of CPM even harder to understand. The ability to better define inherited breast cancer risk by genetic analysis of BRCA1 or 2 mutations does identify a group of patients at greatly increased lifetime risk of contralateral breast cancer (CBC). This segment of the population does not account for the sharp increase in CPM. It appears that many physicians and surgeons believe the risk of contralateral breast cancer to be sufficiently high to justify advising CPM. This risk is often overestimated by both healthcare providers and patients. The case for additional surgery should involve considerations of risk versus benefit, mortality being the principal patient concern and morbidity secondary. Yet there is some morbidity in adding a second mastectomy, and no evidence of mortality benefit. Invasive lobular carcinoma is considered by some physicians to represent an increased risk of contralateral cancer, but that has not proved to be correct. Women with lobular carcinoma in situ or atypical ductal hyperplasia found at the time of their cancer diagnosis are sometimes advised to consider CPM. Treatment with tamoxifen has shown a 50-75% reduction in risk from these tissue findings. Chemotherapy for the primary breast cancer also lowers contralateral risk by about 20%. Symmetry is another reason some have recommended CPM. Reduction can be performed rather than mastectomy, if required. The use of skin-sparing mastectomy has greatly reduced the incidence of any surgery needed for symmetry on the contralateral breast. MRI used to "stage the breast" can raise questions by noting small foci of enhancement in the contralateral breast. Some women elect CPM rather than biopsy or further imaging of the contralateral breast. The case can be made that CPM should be on the decline. Its increase raises questions of the awareness of breast oncologists, medical and surgical, of the true risk data.