Endoscopic Therapy of Colorectal Polyps Douglas K Rex Indiana - - PowerPoint PPT Presentation

Endoscopic Therapy of Colorectal Polyps

Douglas K Rex Indiana University Medical Center Indianapolis, IN

Topics listed in the brochure

• Realistic miss rate of significant polyps during

colonoscopy

• Is withdrawal time a realistic quality indicator?
• Is repeat colonoscopy ever justified for missed polyps?
• Does the data showing the reduction of colon cancer

by screening colonoscopy factor in missed polyps and flat lesions?

• What to do with diminutive polyps?
• Not covered: Endoscopic therapy of colorectal polyps

(but we can discuss it in the Q and A)

Realistic miss rate for “significant polyps”

• Rex tandem colonoscopy study: 6% (2/32) for

adenomas ≥ 10 mm

• CTC studies

– Pickhardt: 12% – Van Gelder: 17%

• In clinical practice you can’t measure the miss

rate: you can only infer it from what is detected (the adenoma detection rate)

– Barclay (Rockford) and Chen (Indiana): a group of endoscopists misses more than half of the large adenomas

Why don’t we measure large adenoma detection rates?

• Harder to specify the expected range and

acceptable thresholds

• Subject to operator error in measuring

polyp size

• Have to examine 5-10 times as many

records

• In both the Rockford and Indiana studies

large adenoma detection correlated with

• verall adenoma detection

Is withdrawal time a realistic quality indicator?

• Primary measure of the quality of mucosal

inspection is the ADR

• Withdrawal time is a secondary indicator; it

does not explain all variation in ADR

– Consistent statistical correlation across studies – Increasing WT increased ADR in the Rockford study (not in a study from Boston)

Withdrawal time as a quality indicator

• Easy to measure (record cecal intubation

times – WT counted only if no polypectomy or biopsies performed)

• Emerging as a standard of care issue

despite warnings of USMSTF and ASGE/ACG

• Should be measure in all patients
• Should be first focus if the ADR is low

Does the reduction of colon cancer by screening colonoscopy factor in missed polyps and flat lesion?

• Which data are you speaking of?

– No RCT of screening colonoscopy – 1 cohort study of screening colonoscopy (Kahi et al CGH 2009) – Multiple adenoma cohorts: NPS, U.S. dietary trials, U.S. chemoprevention trials, Funen adenoma study – Case control studies: Brenner, Muller – Sonnenberg, Singh, Baxter

Does the reduction of colon cancer by colonoscopy factor in missed polyps and flat adenomas?

• Of the various causes of interval cancers,

quantitative assignment of the causes is not currently possible

Why do interval cancers occur?

What to do with diminutive polyps?

• Current policy: resect all except ok to

sample multiple diminutive rectosigmoid polyps that look hyperplastic

• Future policies:

– Leave diminutive HP polyps in the distal colon in place; use photo as documentation

• f histology

– “Resect and discard” diminutive polyps

Accurate real time histology techniques

• Narrow band imaging with and without HM
• FICE
• I Scan
• Confocal laser microscopy
• Endocytoscopy
• Chromoendoscopy with high magnification