Role of colonoscopy and polyp characteristics in colorectal cancer after colonoscopic polyp detection: a population-based case-control study

Ann Intern Med. 2012 Aug 21;157(4):225-32. doi: 10.7326/0003-4819-157-4-201208210-00002.


Background: Studies have identified characteristics of adenomas detected on colonoscopy to be predictive of adenoma recurrence.

Objective: To assess the role of both colonoscopy-related factors and polyp characteristics on the risk for colorectal cancer after colonoscopic polyp detection.

Design: Population-based case-control study (3148 case participants and 3274 control participants).

Setting: Rhine-Neckar region of Germany.

Patients: Case and control participants with physician-validated detection of polyps (other than hyperplastic polyps) at a previous colonoscopy in the past 10 years.

Measurements: Detailed history and results of previous colonoscopies were obtained through interviews and medical records. Case and control participants were compared according to colonoscopy-related factors (incompleteness, poor bowel preparation, incomplete removal of all polyps, and no surveillance colonoscopy within 5 years) and polyp characteristics (≥ 1 cm, villous components or high-grade dysplasia, ≥ 3 polyps, and ≥ 1 proximal polyp). Odds ratios (ORs) and attributable fractions were derived by using multiple logistic regression and the Levin formula.

Results: 155 case participants and 260 control participants with physician-validated polyp detection in the past 10 years were identified. The following characteristics were significantly more common among case participants than among control participants: not all polyps completely removed (29.0% vs. 9.6%; OR, 3.73 [95% CI, 2.11 to 6.60]), no surveillance colonoscopy within 5 years (26.5% vs. 11.5%; OR, 2.96 [CI, 1.70 to 5.16]), and detection of 3 or more polyps (14.2% vs. 7.3%; OR, 2.21 [CI, 1.07 to 4.54]). Odds ratios ranged from 1.12 to 1.42 and CIs included 1.00 for all other variables. Overall, 41.1% and 21.7% of cancer cases were statistically attributable to colonoscopy-related factors and polyp characteristics, respectively.

Limitation: This was an observational study with potential for residual confounding and selection bias.

Conclusion: Colonoscopy-related factors are more important than polyp characteristics for stratification of colorectal cancer risk after colonoscopic polyp detection in the community setting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma / pathology*
  • Adenoma / surgery*
  • Adult
  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Colonic Polyps / pathology*
  • Colonic Polyps / surgery*
  • Colonoscopy*
  • Colorectal Neoplasms / diagnosis*
  • Female
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Patient Compliance
  • Risk Factors
  • Treatment Outcome