Abstract

Familial cases of non-polyposis colorectal cancer have attracted much interest but little is known of their natural history. Using a population based study we have determined whether a positive family history of bowel cancer is an independent prognostic factor. All patients under 55 years with histologically confirmed colorectal cancer in Northern Ireland during the period 1976-8 were studied. The family history was validated in 95% of all nonpolyposis cases (n = 205). Medical history or cause of death were verified for 98% of 1811 first degree relatives. The strength of the family history was assessed using a score that compares the mortality from bowel cancer in the family against the average population mortality, taking account of family size and age structure. The family history score was not predictive of survival neither in univariate analysis or in a Cox's proportional hazards multivariate analysis controlling for age, sex, stage, site, and duration of symptoms. In conclusion, a positive family history does not independently influence prognosis in patients with bowel cancer.