Are breast density and family history associated with pre-operative breast MRI use?

e17543 Background: Pre-operative breast magnetic resonance imaging (MRI) use among women with newly diagnosed breast cancer is increasing. National Comprehensive Cancer Network guidelines state MRI is optional for invasive breast cancer, with no further specifications by patient factors such as breast density or family history of breast cancer. However, these risk factors may influence MRI use decisions, but their association with utilization is unknown. Methods: We used 2005-2010 Breast Cancer Surveillance Consortium data linked to administrative data (Medicare or HMO) to assess the association of mammographic breast density and family history of breast cancer with pre-operative MRI use. We included 3,270 women age > 65 with stage 0-III breast cancer. We used multivariable logistic regression to estimate adjusted odds ratios (OR) for the association of MRI use with density (fatty/scattered vs. heterogeneous/extremely dense) and family history, adjusting for patient and tumor characteristics. Results: Pre-operative MRI use was 13.6% in women with DCIS (n = 563) and 18.1% in women with invasive cancer (n = 2,707). The unadjusted proportion of women receiving breast MRI was similar by breast density (DCIS: 13.7% in women with less and more dense breasts; invasive: 17.9% among less dense vs. 18.3% among more dense) and family history (DCIS: 12.3% family history vs. 14.1% no family history; invasive: 19.4% family history vs. 17.7% no family history). Adjusted models found no difference in pre-operative MRI use by breast density (DCIS: OR = 0.93 for more vs. less dense,95%CI:0.56-1.54; invasive: OR = 0.92,95%CI:0.74-1.14) or family history (DCIS: OR = 0.81,95%CI: 0.45-1.44; invasive: OR = 1.07,95%CI:0.84-1.37). Conclusions: Among women ages 65+ with newly diagnosed breast cancer, two common risk factors, family history and breast density, were not associated with receipt of pre-operative MRI. Additional studies should examine if these risk factors influence utilization in younger women.