Breast cancer screening adherence after multigene panel testing among women with pathogenic variants in moderate-risk genes or with empirically increased breast cancer risk.

To identify factors associated with adherence to breast cancer (BC) screening among women with a pathogenic or likely pathogenic (P/LP) variant in a moderate-risk gene, ATM, BARD1, CHEK2, RAD51C, and RAD51D or with empiric lifetime risk ≥ 20%. We reviewed medical records of women without breast cancer who underwent genetic counseling and testing and were advised to undergo annual breast MRI and mammography. Adherence to screening for up to three years was compared between women with a P/LP variant in a moderate-risk gene and women with an elevated empiric risk of 20-40% by the Tyrer-Cuzick model. The study population included 44 women with P/LP variants (P/LP group) and 117 with lifetime BC estimates of 20-40% (Empiric group). Within one year, the P/LP group had significantly higher rates of screening than the Empiric group with 58% vs. 37% obtaining breast MRI and 88% vs. 55% obtaining mammograms. Time-to-event analysis demonstrated the P/LP group initiated screening significantly sooner than the Empiric group. After adjusting for having family history of BC or personal history of non-BC, the P/LP group was 3.18 and 7.04 times more likely to obtain breast MRI and mammograms, respectively. Adherence declined in both groups in the second and third year of follow-up. Women with P/LP variants were more adherent to BC screening than those with empiric risk, underscoring the role that genetic test results may play in screening behavior. Future efforts should focus on understanding the barriers to screening and improving long-term adherence.