The risk of prostate cancer increases with the number of family members with the disease, particularly brothers, and with younger age at diagnosis, a nationwide study has shown. The national Swedish family cancer database was used to estimate age-specific familial risks of being diagnosed with prostate cancer according to the number and type of affected first-degree relatives and according to paternal and fraternal age at diagnosis. The registry includes records of >11.8 million individuals and their cancers over nearly 50 years. The authors also calculated the risk of dying from prostate cancer according to family history. This is the largest family study published with more than 26,000 prostate cancer cases, of which 5,600 were familial. 'The take home message... is that the risk of prostate cancer increases with the number of affected first-degree family members, particularly brothers, and with younger age at diagnosis. Therefore, patients who fall into higher-risk groups can be identified.'