Helping breast cancer patients analyze risk

Defining the threshold for the amount of risk that an individual woman finds to be acceptable, however, can be a very difficult and personal decision. Even after a patient comes to understand that CPM is unlikely to provide a survival advantage, she may continue to request bilateral surgery purely for the risk-reducing benefits, and out of a desire to minimize her chances of having to repeat the breast cancer diagnosis and treatment experience. In some cases this choice will be influenced by reconstruction factors. A woman may be motivated to pursue bilateral surgery if she has an adequate volume of abdominal tissue because of the fact that the autogenous TRAM (transverse rectus abdominis myocutaneous) flap can be harvested only once. In other cases the decision is influenced by body habitus, for example, a woman with large pendulous breasts who is not interested in breast reconstruction may decide that she is more comfortable with a symmetrically flat chest wall in order to avoid chest wall imbalance and the inconvenience of finding/wearing a prosthesis that matches the remaining breast.

As breast cancer surgeons we should openly discuss these issues with our patients and present viable alternatives when feasible, such as reduction mammoplasty for the large-breasted patient. Ultimately, however, the patient must decide the surgical approach that provides her with the optimal sense of treatment satisfaction, quality of life, and comfort.

Discussion strategies

In my own practice I have found two discussion strategies to be particularly useful in guiding patients through the decision about CPM.

The first approach is relevant for women who are lumpectomy candidates, but who express a "reflex" interest in bilateral mastectomy while they are still in the emotional fog of processing the new cancer diagnosis. For these women it is obviously important to stress the survival equivalence of mastectomy and breast-conserving surgery, and this is also a great opportunity to educate patients about the potential axillary surgery advantages of breast conservation. The American College of Surgeons Oncology Group Z11 trial (JAMA 2011;305:69-75) has provided strong evidence supporting the safety of avoiding an axillary lymph node dissection (ALND) in women with sentinel lymph node (SLN) metastatic disease if the primary breast cancer is managed by lumpectomy and breast radiation.

At this point in time, we do not have comparably strong data to justify avoiding the ALND in the setting of mastectomy patients with SLN metastatic disease. The mastectomy patient with SLN metastasis is usually committed to undergo the completion axillary lymph node dissection specifically so that definitive decisions can be made regarding the need for postmastectomy radiation, and many of these patients become ineligible for immediate reconstruction because of this possible radiation. I therefore accentuate the advantage of at least initiating treatment with lumpectomy and sentinel lymph node biopsy. The patient preserves all of her surgical options with the benefit of having more staging information. If she is found to have SLN metastatic disease then she is in a better position to avoid the ALND with lumpectomy and radiation, and the option of future mastectomy and immediate reconstruction would still be available to her in the future (after completing all of her cancer treatment and healing from her radiation); if the SLN is negative, she can either continue with the breast-conservation treatment plan or she can pursue mastectomy (with or without immediate breast reconstruction, since prophylactic mamillary radiation therapy is not likely to be indicated for node-negative disease).

The second approach is relevant to the patient requiring mastectomy but for whom delayed reconstruction is planned because of medical issues or anticipated postmastectomy radiation. I encourage these patients to at least consider deferring the decision for the CPM until they return for the delayed reconstruction of the cancerous mastectomy, because at that time they can undergo the prophylactic mastectomy with the cosmetic advantages of immediate reconstruction.

Cost considerations

From the public health and population-based breast cancer burden perspectives as well as for individual patients, there are additional issues to be factored into the CPM discussion. It is a basic reality that cost is relevant when it comes to sorting out the net benefit of particular medical interventions, especially those that are prophylactic. Interestingly, a cost analysis study by Zendejas et al. (J. Clin. Oncol. 2011;29:2993-3000) from the Mayo Clinic demonstrated that CPM is actually cost effective, compared with surveillance for patients diagnosed when they are younger than 70 years of age.

The Women’s Health and Cancer Rights Act was implemented in 1999, mandating insurance coverage for breast reconstruction after mastectomy performed for cancer. This legislation promoted more widespread acceptance (and reimbursement) for contralateral mastectomy/reconstruction, but patients should nonetheless be proactive about confirming that their individual policy will indeed cover the expenses of prophylactic surgery. Furthermore, we must continue to monitor outcomes in women who choose to undergo CPM, as advances in breast cancer therapies may influence the survival benefits of this surgical approach. Indeed, selected retrospective studies have recently demonstrated that patients undergoing CPM have an improved survival, compared with those focusing on unilateral breast cancer surgery (Ann. Surg. Oncol. 2010;17:2702-9; J. Natl. Cancer Inst. 2010;102:401-9; J. Clin. Oncol. 2005;23:4275-86; Am. J. Surg. 2000;180:439-45). These results suggest a survival advantage associated with avoidance of a contralateral breast cancer, in contrast to the historical data alluded to above, regarding survival equivalence for patients with unilateral compared to metachronous bilateral breast cancer. As adjuvant systemic therapies for breast cancer continue to improve in effectiveness and ability to completely eliminate distant organ micrometastases, it is likely that we will continue to increase the pool of women who are essentially "cured" of the first cancer. This in turn could potentially increase the longevity threat of a second/metachronous cancer though a renewed metastatic risk. Nonetheless, data on possible survival advantages of CPM have not yet matured to the point where it can be recommended as a medically "indicated" procedure.