Colorectal polyp counts and cancer risk in familial adenomatous polyposis

Gastroenterology. 1996 Apr;110(4):1028-30. doi: 10.1053/gast.1996.v110.pm8612989.


Background & aims: In familial adenomatous polyposis, colorectal cancer prevention is by prophylactic colectomy, but dietary or chemopreventative strategies have been recently proposed in low-risk individuals. The aim of this study was to define predictive risk factors for colorectal cancer in familial adenomatous polyposis.

Methods: Between 1918 and 1993, 317 patients underwent colectomy. A multivariate analysis was performed to assess the relationship between colorectal cancer risk and polyp count, sex, and age at colectomy.

Results: The median polyp count was 842 (range, 78-7500), and cancer was found in 22% of patients. Polyp count and age, but not sex, predicted cancer risk. Patients with >1000 polyps had 2.3 times greater risk of cancer than those with <1000 polyps (P=0.006). Synchronous cancers increased with poly count (P<0.05). Each 10-year age group had a 2.4-fold difference in cancer risk (95% confidence interval, 1.9-3.2; P<0.001). Four cases of cancer occurred in patients at low risk (younger than 30 years of age, <1000 polyps; 3.3%).

Conclusions: More adenomas and older age are associated with a higher risk of colorectal cancer. However, cancer does occur in low-risk individuals and may be missed by surveillance, making alternatives to prophylactic surgery inadvisable.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenomatous Polyposis Coli / pathology*
  • Adenomatous Polyposis Coli / surgery
  • Adolescent
  • Adult
  • Age Factors
  • Child
  • Colectomy
  • Colon / pathology*
  • Colorectal Neoplasms / epidemiology
  • Colorectal Neoplasms / pathology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Probability
  • Rectum / pathology*
  • Risk Factors