Role of chance in familial aggregation of colorectal cancer

A prospective population-based study recorded family trees of 77 colorectal cancer patients younger than 50 years of age. Using mathematical modeling of population age-incidence data, we estimate that 1 (95% confidence limits 0 and 3) of these families is expected to meet the Amsterdam criteria I for HNPCC due to chance clustering of colorectal cancer. © 2001 Cancer Research Campaign