The CanRisk Tool uses two risk models to estimate breast and ovarian cancer risks: the BOADICEA Model and the Ovarian Cancer Model. These models are periodically updated in order to: (i) incorporate additional information in risk calculations (e.g. new genes and risk factors); and (ii) ensure that they are based on the most up-to-date epidemiological data. For example, when we have released previous versions of the software in the past, we have updated: population cancer incidence rates, relative risks, mutation search sensitivities and pathology distributions for mutation carriers. These updates ensure that the risks predicted by the tool are as reliable as possible based on the latest evidence. However, this also explains why some results obtained with the latest version of the tool differ from those obtained using previous versions of the software.