Predictors of contralateral prophylactic mastectomy and the impact on breast reconstruction.

BACKGROUND: Contralateral prophylactic mastectomy (CPM) is being performed with increased frequency. Predictors of CPM and their impact on breast reconstruction are examined.
METHODS: A retrospective review of a dually trained oncologic and plastic surgeon's experience with patients undergoing total mastectomy from 2002 to 2012 was performed. Patients who underwent bilateral therapeutic mastectomies or who had previous contralateral mastectomy were excluded from this series.
RESULTS: Four hundred forty-six patients were treated with total mastectomy and 174 (39%) underwent CPM. The incidence of CPM nearly tripled over the period studied. Compared to women treated with unilateral mastectomy, women who elected for CPM were younger (mean age, 50.4 vs 56.8 years, P < 0.001), leaner (mean body mass index, 26.1 vs 27.4 kg/m2, P = 0.036), more often white (86.8% vs 73.8%, P = 0.004), and more often had a family history of breast cancer (52% vs 33.3%, P < 0.001). The CPM group was also more likely to have undergone a preoperative magnetic resonance imaging (56.3% vs 39%, P < 0.001) and to have stage I disease (31% vs 22.8%, P = 0.053). They were less likely to have undergone prior attempts at breast conservation (6.9% vs 15.8%, P = 0.004) and considerably more likely to pursue breast reconstruction (83.9% vs 63.6%, P < 0.001). Multivariate analysis confirmed age, white race, family history, prior attempt at breast conservation, and receipt of breast reconstruction to be independently associated with prophylactic mastectomy. Incidental contralateral cancers were discovered in 4% of women who underwent CPM (n = 7), lobular carcinoma in situ in 2.3% (n = 4), and atypical lesions in an additional 11.6% (n = 20). Women who underwent CPM favored reconstruction with breast implants (60.9% vs 17.3%), whereas the transverse rectus abdominis musculocutaneous flap predominated among their unilateral counterparts (38.6% vs 15.5%). Among women who underwent immediate breast reconstruction, the addition of a contralateral procedure expectedly increased breast complication rates (50.3% vs 35.0%, P = 0.007), especially the more severe complications that required hospitalization or reoperation (18.6% vs 5.0%, P < 0.001).
CONCLUSIONS: The incidence of CPM is increasing and is associated with younger age, white race, family history, and the use of breast reconstruction. Implant-based reconstructions predominate in this cohort. The added morbidity of a contralateral procedure is significant.