When is colonoscopy necessary? - Distal-proximal adenoma relationships in the polyp prevention trial (PPT)

R. E. Schoen, J. Weissfeld, R. Burt, P. Lance, F. Iber, D. Corle, L. Cranston, M. Hassen, K. Lewin, H. Appleman, A. Schatzkin

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The need for colonoscopy in individuals with low risk distal adenomas found on sigmoidosocopy is a controversial and important screening issue. AIM: To examine the prevalence of advanced (adv) proximal adenomas in patients (pts) with non-advanced distal adenomas in a large cohort with central pathologic review. METHODS: The PPT is a multi-center randomized study (N=2079) of dietary intervention on adenoma recurrence. Using the index colonoscopy prior to randomization, pts with distal adenomas (distal to splenic flexure or ≤50 cm) and no prior history of adenoma or previous colonsocopy were included (N=1123). Relationships between distal and adv proximal adenomas were examined. RESULTS: Mean age 60, 38% female, 10% minority. 45.6% of the distal polyps (512/1123) were adv, i.e., had a villous component, HG Dysplasia (HGD), or were ≥1cm. 18.7% (48/257) of the proximal adenomas were adv. 4.3% of all patients had an adv proximal adenoma (48/1123). Villous Histology: 2.9% of pts with distal villous compared to 1.4% of pts w/o distal villous had a proximal villous lesion (OR 2.1, p=NS). HGD: 3.5% of pts with distal HGD compared to 0.8% of pts w/o distal HGD had proximal HGD (OR 4.8, p=.03). ≥1cm: 4.2% of pts with distal ≥1cm compared to 3.0% of pts w/o distal ≥1cm had a proximal ≥1cm lesion (OR 1.4, p=NS). Overall, 5.7% of pts (29/512) with a distal adv lesion compared to 3.1% of pts (19/611) w/o a distal adv lesion had a proximal adv lesion (OR 1.9, 95%CI 1.0, 3.5, p=.05). Altering the definition of a distal/proximal lesion did not change the results. CONCLUSIONS: 1) Pts with an adv distal adenoma are about twice as likely to have an adv proximal adenoma. 2) 3.1% of pts w/o an adv distal adenoma had an adv proximal adenoma. Not performing a colonoscopy in patients with a distal non-adv adenoma in this cohort would have missed 40% (19/48) of the proximal adv adenomas. 3) These results support performing a colonoscopy in pts with a non-adv distal adenoma found on flexible sigmoidoscopy.

Original languageEnglish (US)
Pages (from-to)AB117
JournalGastrointestinal endoscopy
Issue number4
StatePublished - 1997

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Gastroenterology


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