AGA Clinical Practice Update: Strategies to Improve Colonoscopy Quality

Will Pass

August 12, 2021

The American Gastroenterological Association recently issued a clinical practice update outlining tenets of high-quality colonoscopy screening and surveillance.

The update includes 15 best practice advice statements aimed at the endoscopist and/or endoscopy unit, reported lead author Rajesh N. Keswani, MD, of Northwestern University, Chicago, and colleagues.

"The efficacy of colonoscopy varies widely among endoscopists, and lower-quality colonoscopies are associated with higher interval CRC [colorectal cancer] incidence and mortality," the investigators wrote in Gastroenterology.

According to Keswani and colleagues, quality of colonoscopy screening and surveillance is shaped by three parameters: safety, effectiveness, and value. Some metrics may be best measured at a unit level, they noted, while others are more clinician specific.

"For uncommon outcomes (e.g., adverse events) or metrics that reflect system-based practice (e.g., bowel preparation quality), measurement of aggregate unit-level performance is best," the investigators wrote. "In contrast, for metrics that primarily reflect colonoscopist skill (e.g., adenoma detection rate), endoscopist-level measurement is preferred to enable individual feedback."

Endoscopy Unit Best Practice Advice

According to the update, endoscopy units should prepare patients for, and monitor, adverse events. Prior to the procedure, patients should be informed about possible adverse events and warning symptoms, and emergency contact information should be recorded. Following the procedure, systematic monitoring of delayed adverse events may be considered, including "postprocedure bleeding, perforation, hospital readmission, 30-day mortality, and/or interval colorectal cancer cases," with rates reported at the unit level.

Ensuring high-quality bowel preparation is also the responsibility of the endoscopy unit, according to Keswani and colleagues, and should be measured at least annually. Units should aim for a Boston Bowel Preparation Scale score of at least 6, with each segment scoring at least 2, in at least 90% of colonoscopies. The update provides best practice advice on split-dose bowel prep, with patient instructions written at a sixth-grade level in their native language. If routine quality measurement reveals suboptimal bowel prep quality, instruction revision may be needed, as well as further patient education and support.

During the actual procedure, a high-definition colonoscope should be used, the expert panel wrote. They called for measurement of endoscopist performance via four parameters: cecal intubation rate, which should be at least 90%; mean withdrawal time, which should be at least 6 minutes (aspirational, ≥9 minutes); adenoma detection rate, measured annually or when a given endoscopist has accrued 250 screening colonoscopies; and serrated lesion detection rate.

Endoscopist Best Practice Advice

Both adenoma detection rate and serrated lesion detection rate should also be measured at an endoscopist level, with rates of at least 30% for adenomas and at least 7% for serrated lesions (aspirational, ≥35% and ≥10%, respectively).

"If rates are low, improvement efforts should be oriented toward both colonoscopists and pathologists," the investigators noted.

A variety of strategies are advised to improve outcomes at the endoscopist level, including a second look at the right colon to detect polyps, either in forward or retroflexed view; use of cold-snare polypectomy for nonpedunculated polyps 3-9 mm in size and avoidance of forceps in polyps greater than 2 mm in size; evaluation by an expert in polypectomy with attempted resection for patients with complex polyps lacking "overt malignant endoscopic features or pathology consistent with invasive adenocarcinoma"; and thorough documentation of all findings.

More broadly, the update advises endoscopists to follow guideline-recommended intervals for screening and surveillance, including repeat colonoscopy in 3 years for all patients with advanced adenomas versus a 10-year interval for patients with normal risk or "only distal hyperplastic polyps."

Resource-Limited Institutions and a Look Ahead

Keswani and colleagues concluded the clinical practice update with a nod to the challenges of real-world practice, noting that some institutions may not have the resources to comply with all the best practice advice statements.

"If limited resources are available, measurement of cecal intubation rates, bowel preparation quality, and adenoma detection rate should be prioritized," they wrote.

They also offered a succinct summary of outstanding research needs, saying "we anticipate future work to clarify optimal polyp resection techniques, refine surveillance intervals based on provider skill and patient risk, and highlight the benefits of artificial intelligence in improving colonoscopy quality."

This clinical practice update was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board. Keswani consults for Boston Scientific. The other authors had no disclosures.

This article originally appeared on, part of the Medscape Professional Network.


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