Background: Subjects with a positive family history of
colorectal cancer (CRC) have an increased risk of developing CRC themselves. This risk depends on the number of affected relatives and the age at diagnosis.
Aim: The aim of this study was to assess the prevalence of a positive family history of CRC, within a random cohort among the dutch population.
Methods: A total of 5072 subjects aged between 45 and 70 years were invited to fill in an anonymous questionnaire about the occurrence of CRC in their first-degree relatives (FDR).
Results: The questionnaire was returned by 3973 subjects (78.3%). Thirty responders (0.8%) had CRC themselves. Of all unaffected responders, 441 (11.2%) subjects reported a positive family history of CRC. Ninety (2.3%) responders reported having an FDR with CRC diagnosed before the age of 50, or reported two or more FDRs with CRC.
Conclusion: The prevalence of a positive family history of CRC is substantial. Identification of this high-risk group by obtaining a thorough family history is the first step in targeting preventive measures.