Likelihood of missed and recurrent adenomas in the proximal versus the distal colon

Adeyinka O. Laiyemo, Chyke Doubeni, Andrew K. Sanderson, Paul F. Pinsky, Dilhana S. Badurdeen, V. Paul Doria-Rose, Pamela M. Marcus, Robert E. Schoen, Elaine Lanza, Arthur Schatzkin, Amanda J. Cross

Research output: Contribution to journalArticlepeer-review


Background: Colonoscopy may be less efficacious in reducing colorectal cancer mortality in the proximal compared with the distal colon. A greater likelihood for missed and recurrent adenomas in the proximal colon may contribute to this phenomenon. Objective: To examine whether a proximal adenoma is associated with the risk and location of missed and recurrent adenomas. Design: Prospective. Setting: Polyp Prevention Trial. Participants: A total of 1864 patients with an adenoma at baseline underwent a follow-up colonoscopy 4 years later (adenoma recurrence). Of these, 1731 underwent a clearing colonoscopy 1 year after the baseline examination (missed adenoma). Main Outcome Measurements: Association of baseline adenoma location with the risk and location of adenomas found at colonoscopy performed 1 year and 4 years later. Results: At the year 1 colonoscopy, 598 patients (34.6%) had an adenoma (missed adenoma). Compared with those with a distal-only adenoma at baseline, patients with a proximal-only adenoma at baseline were more likely to have any missed adenomas (relative risk [RR] 1.28; 95% CI, 1.09-1.49) and a proximal-only missed adenoma (RR 2.05; 95% CI, 1.49-2.80). At the year 4 colonoscopy, 733 patients (39.3%) had adenoma recurrence. Patients with a baseline proximal-only adenoma were more likely to have any adenoma recurrence (RR 1.14; 95% CI, 1.00-1.31) and a proximal-only adenoma recurrence (RR 1.52; 95% CI, 1.15-2.02). Sensitivity analyses involving missed adenomas did not materially affect the risk or location of recurrent adenomas at year 4 colonoscopy. Limitation: Lesions may still be missed on repeated colonoscopies. Conclusions: Missed and recurrent adenomas are more likely to be in the proximal colon.

Original languageEnglish (US)
Pages (from-to)253-261
Number of pages9
JournalGastrointestinal endoscopy
Issue number2
StatePublished - Aug 2011
Externally publishedYes


  • PPT
  • Polyp Prevention Trial
  • RR
  • relative risk

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Gastroenterology


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