Building absolute breast cancer risk prediction models for women treated with chest radiation for Hodgkin lymphoma.

We built models to predict absolute breast cancer (BC) risk in women treated with radiotherapy for Hodgkin lymphoma (HL). We first estimated relative risks (RRs) for risk factors, including radiation dose to 10 breast segments to accommodate heterogeneity of treatment effects, using a case-control sample nested in an HL survivor cohort. To estimate RRs of case-control matching factors we developed novel weighting approaches. We then combined RRs with age-specific BC incidence and competing mortality rates from the HL survivor cohort and a population-based registry, accommodating differences between them. We compared the performance of models using segment-specific doses with using mean dose only.