Clinical management factors contribute to the decision for contralateral prophylactic mastectomy

To determine whether increasing rates of contralateral prophylactic mastectomy (CPM) are due to recognition of risk factors for contralateral breast cancer (CBC) or treatment factors related to the index lesion.

From 1997 to 2005, 2,965 patients with stage 0 to III primary unilateral breast cancer underwent mastectomy at Memorial Sloan-Kettering Cancer Center. Patients who did and did not undergo CPM within 1 year of treatment for their index cancer were compared to identify independent predictors of CPM.

The rate of CPM was 13.8% (n = 407), increasing from 6.7% in 1997 to 24.2% in 2005 (P < .0001). Patients with BRCA mutations or prior mantle radiation (n = 52) accounted for 13% of those having CPM. The rate of CPM by surgeon varied from 1% to 26%. Multivariate logistic regression adjusting for surgeon-identified white race (odds ratio [OR] = 3.3), immediate reconstruction (OR = 3.3), family history of breast cancer (OR = 2.9), magnetic resonance imaging (MRI) at diagnosis (OR = 2.8), age younger than 50 years (OR = 2.2), noninvasive histology (OR = 1.8), and prior attempt at breast conversation (OR = 1.7) to be independent predictors of CPM.

These data suggest that increasing use of CPM is not associated with increased recognition of patients at high risk for CBC. Treatment factors, such as immediate reconstruction, preoperative MRI, and unsuccessful attempts at breast conservation, are associated with increased rates of CPM. Efforts to optimize breast conservation, minimize unnecessary tests, and improve patient education about the low risk of CBC may help to curb this trend.