Geographic and patient characteristics associated with election of prophylactic mastectomy in young breast cancer patients with early disease

Objectives: To examine the association between geography and utilization rates of contralateral prophylactic mastectomy (CPM) relative to patient-level factors in patients with early stage breast cancer. Materials and Methods: Using the Truven Health MarketScan Commercial Database, a descriptive analysis of geographic variation in genetic testing and CPM rates of 38,108 women ages 18 to 64 years treated with surgery for invasive unilateral breast cancer between 2010 and 2012 was conducted. Multivariate hierarchical analysis was used to examine the relationship between CPM likelihood and patient characteristics, with metropolitan statistical area (MSA) serving as a random effect. Patient characteristics included age group, BRCA1/2 carrier status, family history of breast cancer, breast surgery type, radiation therapy, drug therapy, and payer type. All MSAs in the United States were included, with areas outside MSAs within a given state aggregated into a single area for analytical purposes. Results: Descriptive analysis demonstrated significant geographic variation in rates of CPM irrespective of risk inferred from primary malignancy treatment course (P<0.01 to <0.001). Odds of CPM were higher among BRCA1/2 carriers (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.52-2.06), followed by MSA (median OR among all MSAs was 1.61; 95% CI, 1.51-1.73) and family history of breast cancer (OR, 1.49; 95% CI, 1.28-1.53), respectively. Patients who were not tested for BRCA1/2 were less likely (OR, 0.66; 95% CI, 0.61-0.71) to undergo CPM than patients with a negative BRCA test. Conclusions: The large geographic variation we observed in CPM indicate a need to understand and optimize clinical decision-making.