Calculating, Using and Improving Individual Breast Cancer Risk Estimates

Breast cancer risk assessment is important in order to identify individuals at extremely high risk who would be potential candidates for prophylactic surgery or preventive therapy, those at a moderately enhanced risk who might benefit from enhanced surveillance and potentially those at sufficiently low risk as to not require surveillance or risk management. Women with a substantial family history of the disease qualify for genetic testing of high-risk BRCA1/2 genetic alterations. For women without mutations in high-risk genes, or without a large family history, the current state of the art for risk assessment combines classical questionnaire risk factors (including information on hormonal and reproductive factors), mammographic density and genetic testing through polygenic risk scores. Risk models for these components alone and their combination have shown a degree of accuracy in prediction of invasive breast cancer risk. In this chapter, we consider how risk models are calculated, their potential clinical use and the targets for research in the future to improve risk assessment in order to better inform risk management and surveillance.