Inclusion of endogenous plasma dehydroepiandrosterone sulphate and mammographic density in risk prediction models for breast cancer

Background: Endogenous hormones and mammographic density are risk factors for breast cancer. Joint analyses of the two may improve the ability to identify high-risk women. Methods: This study within the KARMA cohort included prediagnostic measures of plasma hormone levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), and mammographic density in 629 cases and 1,223 controls, not using menopausal hormones. We evaluated the area under the receiver-operating curve (AUC) for risk of breast cancer by adding DHEA, DHEAS, and mammographic density to the Gail or Tyrer–Cuzick 5-year risk scores or the CAD2Y 2-year risk score. Results: DHEAS and percentage density were independently and positively associated with breast cancer risk (P = 0.007 and P Conclusions: DHEAS and mammographic density are independent risk factors for breast cancer and improve risk discrimination for postmenopausal breast cancer. Impact: Combining DHEAS and mammographic density could help identify women at high risk who may benefit from individualized breast cancer screening and/or preventive measures among postmenopausal women.