At present, the risk models used by the CanRisk Tool have only been validated for women of European ancestry. Therefore, the CanRisk Tool is most applicable to European populations.  It should, however, work reasonably well in other Western populations.

Iceland populations have higher frequencies of BRCA1 and/or BRCA2 mutations, and modifications to the risk calculations may be required for this population.

The CanRisk Tool has not been evaluated in populations at lower risk of breast cancer (such as far Eastern or developing countries). Predictions in these populations (particularly of the cancer risk) are likely to be unreliable.