The use of contralateral prophylactic mastectomy among elderly patients in the United States.

Purpose: Previous studies have reported increased rates of contralateral prophylactic mastectomy (CPM) in the United States among women with unilateral breast cancer. These trends have primarily focused on younger breast cancer patients. Given the growing aging population in the United States, we sought to determine whether CPM use is also increasing in elderly patients.
Methods: This population-based study identified patients in the surveillance epidemiology and end results (SEER) data. We determined the rate of CPM as a proportion of all surgically treated patients and as a proportion of all mastectomies. We compared the unadjusted CPM rates over the study period using the Cochrane-Armitage test for trend. We used a logistic regression model to test for the factors associated with CPM utilization.
Results: We identified 261,281 patients ≥ 65 years who underwent surgical treatment for breast cancer. For all patients treated with surgery for invasive breast cancer, the use of CPM increased from 1 in 2004 to 3% in 2014 (200% increase). Among mastectomy patients, the use of CPM increased from 3 in 2004 to 7% in 2014 (133% increase). Young age, non-Hispanic white race, lobular histology, higher grade, increased stage, negative lymph node status, and recent year of diagnosis were significantly associated with increased CPM rates.
Conclusions: For elderly patients the use of CPM has continued to increase in the United States. These observations warrant concern in light of increasing evidence that CPM does not improve oncological outcomes and is associated with increased morbidity in older patients.