Background
To support mammography screening decision-making, we developed a competing-risk model to estimate 5-year breast cancer (BC) risk and 10-year non-BC death for women ≥55 using Nurses’ Health Study (NHS) data and examined model performance in the Black Women’s Health Study (BWHS). Here, we examine model performance in predicting 10-year outcomes in the BWHS, Women’s Health Initiative-Extension Study (WHI-ES) and Multiethnic Cohort (MEC) and compare model performance to existing BC prediction models.
Methods
We used competing-risk regression and Royston and Altman’s methods for validating survival models to calculate our model’s calibration and discrimination (c-index) in BWHS (n = 17,380), WHI-ES (n = 106,894) and MEC (n = 49,668). NHS development cohort (n = 48,102) regression coefficients were applied to the validation cohorts. We compared our model’s performance to BCRAT “Gail” and IBIS models by computing BC risk estimates and c-statistics.
Results
When predicting 10-year BC risk, our model’s c-index was 0.569 in BWHS, 0.572 in WHI-ES, and 0.576 in MEC. BCRAT’s c-statistic was 0.554 in BWHS, 0.564 in WHI-ES, and 0.551 in MEC; IBIS’s c-statistic was 0.547 in BWHS, 0.552, in WHI-ES, and 0.562 in MEC. BCRAT underpredicted BC risk in WHI-ES; IBIS underpredicted BC risk in WHI-ES and in MEC but overpredicted BC risk in BWHS. Our model calibrated well. Our model’s c-index for predicting 10-year non-BC death was 0.760 in WHI-ES and 0.763 in MEC.
Conclusions
Our competing-risk model performs as well as existing BC prediction models in diverse cohorts and predicts non-BC death. We are developing a website to disseminate our model.