Breast cancer screening adherence at multiple timepoints over eight years among women in a familial cohort.

Abstract

1557 Background: Since 2007, U.S. guidelines recommend cancer-free women with ≥20% lifetime breast cancer (BC) risk undergo BC screening with mammogram and breast MRI. There is limited long-term data on BC screening adherence among young, high-risk women. To address this knowledge gap, we examined utilization of multiple BC screening modalities over time. Methods: Eligible women were ≥ 30 years old, had no history of BC/ovarian cancer, an intact breast, are enrolled in the Breast and Ovarian Surveillance Service (BOSS) Cohort, and visited the Johns Hopkins Cancer Genetics Clinic for risk assessment within 2 months of cohort enrollment (N = 374). All screening was self-reported at baseline, 4, and 8 years. A subset has been validated. We categorized women by BC risk (Tyrer-Cuzick version) obtained at the clinic. We examined frequency of screening over follow-up, and defined adherence to annual mammography and breast MRI based on age- and risk-based guidelines. We modeled the association between BC risk and adherence at 4 and 8 years using logistic regression. Results: At baseline, the median age was 47 years, 31% had lifetime risk < 20%, and 69% had risk ≥20%. Frequency of mammography and clinical breast exam over follow-up was > 60%, while frequency of breast MRI and breast ultrasound was < 40%. Twenty-five percent of high-risk women at 4 years and 40% at 8 years did not report any mammography, breast MRI, or breast ultrasound. At 4 years, high-risk women were 85% less adherent [multivariable adjusted OR = 0.15; 95%CI = 0.07, 0.34] to BC screening guidelines compared to women with a risk of < 20% due to low uptake of breast MRI, while at 8 years, high-risk women were also less adherent to mammography [multivariable adjusted OR = 0.42; 95%CI = 0.18, 0.95]. We observed similar associations among women at high-risk at 5- and 10-years. Adherence at 4 years predicted adherence at 8 years. Interestingly, women who did not uptake MRI complied with other health screening including for colorectal cancer. Conclusions: High-risk women were not adherent to risk-appropriate BC screening, and adherence did not improve over time. Low adherence appears specific to BC screening. New approaches to BC screening are urgently needed for this high-risk group.