Screening for people with a family history of colorectal cancer

People with one or more first degree relatives affected by colorectal cancer have an increased risk of developing the disease themselves,1 2 3 especially if a relative was affected at an early age (before age 45).2 3 The excess risk is even more marked if the unaffected person reports a family history when aged less than 45.1. Hence, many centres offer colonoscopy every three years or even more frequently to people fulfilling the following criteria: one first degree relative affected by colorectal cancer before the age of 45; two affected first degree relatives; evidence of dominant familial cancer trait including colorectal, uterine, and other cancers. However, in practice even less restrictive criteria are employed. We wish to highlight some concerns about targeting invasive screening using criteria based on family history and to encourage further debate on this issue. About 10% of patients with colorectal cancer have one or more first degree relatives who are affected.2 3 People with a family history are twice as likely as the general population to develop colorectal cancer themselves,1 2 3 but there is considerable variation in the risk to each person.1 2 People from families with …