Complete colonoscopy rarely misses cancer

Gastrointest Endosc. 2002 Feb;55(2):167-71. doi: 10.1067/mge.2002.121190.


Background: The assumption that colonoscopy is highly accurate for detecting colorectal cancer was tested by identifying cancer subsequent to colonoscopy in 2 cohorts of patients in which colonoscopy was reported as normal.

Methods: A multicenter endoscopy database was used to identify all reportedly normal colonoscopies. One cohort was assessed 5 years after colonoscopy with the use of a population-based health services-linked database to link patient morbidity, cancer, and mortality data. The second cohort was assessed by identifying patients who had cancer on repeat colonoscopy.

Results: Of 1047 patients with normal colonoscopies followed for 5 years or until death if earlier, 5 cancers (0.5%) were detected. This rate was not significantly different from that predicted by Australian statistics (risk = 1.0%, p > 0.1), but significantly lower compared with that for all patients presenting for colonoscopy during the study period (risk = 5.2%, p < 0.001). In another cohort of 8486 patients with reportedly normal colonoscopies, 496 patients underwent repeat colonoscopies during an average follow-up of 3.1 years; cancer was diagnosed at the subsequent procedure in 3 patients (0.6%).

Conclusions: The high accuracy of colonoscopy is demonstrated by the low risk of harboring an advanced neoplastic lesion after a normal examination.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Australia / epidemiology
  • Cohort Studies
  • Colonic Polyps / diagnosis
  • Colonic Polyps / epidemiology
  • Colonoscopy / statistics & numerical data*
  • Colorectal Neoplasms / diagnosis*
  • Colorectal Neoplasms / epidemiology
  • Cross-Sectional Studies
  • Databases, Factual
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Mass Screening / statistics & numerical data*
  • Middle Aged
  • Patient Acceptance of Health Care / statistics & numerical data
  • Predictive Value of Tests
  • Risk