Whereas polyposis syndromes are rare, discrete adenomas in small numbers occur in from 10% to 50% of the general population. Overall, colorectal cancer may affect 3% of the population. The inheritance pattern of these cases is largely unknown. Park et al.  studied a large groups with clusters of colorectal cancer. Extensive screening with flexible proctosigmoi-doscopy revealed adenomas in 21% of the 191 pedigree members in contrast to 9% of controls. The excess of adenomas showed autosomal dominant inheritance. A subsequent expanded study of 670 persons in 34 kindreds revealed the estimated prevalence of adenoma at age 60 years in related family members was 24% whereas that in unrelated spouses was 12%. Such studies emphasise the importance of screening for colorectal tumours in first-degree relatives of patients with these lesions.
Was this article helpful?