Significance of a normal surveillance colonoscopy in patients with a history of adenomatous polyps

Dis Colon Rectum. 2000 Aug;43(8):1084-91; discussion 1091-2. doi: 10.1007/BF02236554.


Purpose: The aim of this study was to determine the appropriate surveillance for patients with a history of adenomatous polyps whose last colonoscopic examination was normal.

Methods: This was a retrospective review of a database of 7,677 colonoscopies (1990 to 1996). In patients under colonoscopic surveillance, we reviewed cases of patients who had received three colonoscopies (an index (initial) colonoscopy positive for adenomas and 2 follow-up colonoscopies (interim and final)). The risk of adenomas and cancers at final follow-up colonoscopy was compared between patients having a normal interim colonoscopy and those with a positive interim colonoscopy. The risk at final colonoscopy was also stratified by time interval and the size and number of adenomas at the initial index colonoscopy.

Results: Two hundred four patients undergoing surveillance for adenomas met inclusion criteria. At index colonoscopy the median polyp size was 1 cm and median frequency was three polyps. At all follow-up colonoscopies, we detected 493 adenomas and one cancer (median follow-up, 55 months). At 36 months patients with a normal interim colonoscopy (n = 91) had significantly fewer polyps than patients with a positive interim colonoscopy (n = 113; 15 vs. 40 percent; P = 0.0001). By 40 months, adenomas were detected in more than 40 percent of patients in both groups. The risk after a normal interim colonoscopy was not affected by time interval or number or size of polyps. Adenomas found subsequent to a normal interim colonoscopy were dispersed throughout the colon in 28 patients and isolated to the rectosigmoid in 6 patients.

Conclusions: In patients with a history of adenomas, a normal follow-up colonoscopy is associated with a statistically but not clinically significant reduction in the risk of subsequent colonic neoplasms. These patients require follow-up surveillance colonoscopy at a four-year to five-year interval.

MeSH terms

  • Adenomatous Polyposis Coli / complications*
  • Adenomatous Polyposis Coli / diagnosis
  • Adenomatous Polyposis Coli / pathology
  • Adult
  • Aged
  • Aged, 80 and over
  • Colonic Neoplasms / diagnosis*
  • Colonic Neoplasms / etiology
  • Colonoscopy*
  • Female
  • Humans
  • Male
  • Mass Screening
  • Middle Aged
  • Retrospective Studies
  • Risk Factors
  • Sensitivity and Specificity
  • Time Factors