Prophylactic contralateral surgery: current recommendations and techniques

The use of contralateral prophylactic mastectomy (CPM) from both invasive cancer and ductal carcinoma in situ is increasing in the United States [1], in spite of the fact that only 3% of breast cancer patients in the Surveillance, Epidemiology, and End Results database developed a contralateral cancer at 5 years [2]. Endocrine therapy and trastuzumab, both widely used as adjuvant therapy, reduce the incidence of contralateral cancer by about 50%, suggesting that the risk of contralateral cancer in women treated today is quite low.

Most guidelines for prophylactic mastectomy address women at high risk, not women with unilateral cancer. Known or suspected BRCA mutation carriers who develop unilateral cancer have a 40 to 60% risk of developing a contralateral cancer, and CPM is accepted as appropriate therapy in this circumstance.

To address the issue of what kind of women undergo CPM, we identified 477 patients who had the procedure at Memorial Sloan-Kettering Cancer Center within 1 year of a unilateral cancer diagnosis and compared them with 2,500 women undergoing unilateral mastectomy in the same period (1997 to 2005). CPM patients were younger (median 46 vs 53 years; P < 0.0001), had smaller tumors (1.2 vs 1.8 cm; P < 0.0001), and were less likely to have positive nodes (47 vs 57%; P < 0.0001). Hormone receptor and HER2 status did not differ between cases and controls. Although 68% of CPM patients reported a family history of breast cancer, only 2% underwent genetic testing. Of these, 34 (7%) were found to have a mutation. The pathology specimens of 6% of patients undergoing CPM were found to contain malignancy (eight invasive, 20 ductal carcinoma in situ).

When CPM is performed, it should be done to the same anatomic limit as a therapeutic mastectomy. Skin sparing to facilitate reconstruction is appropriate, but flaps should be the same thickness as is used in a therapeutic mastectomy. The use of nipple sparing is controversial [3]. In order to maintain a blood supply to the nipple areolar complex, some breast tissue must be left behind. Most studies of local recurrence after nipple preservation have been limited to patients with breast cancer, and little is known about its use in the prophylactic setting, particularly regarding risks in BRCA carriers. However, local recurrence is uncommon after nipple sparing for cancer treatment, and improved body image and psychological adjustment after nipple sparing has been reported [3], making this option worthy of consideration in patients undergoing CPM.