Wallace_Michael lab

Michael B. Wallace, MD, MPH

Colorectal cancer (CRC) screening is a major victory for gastroenterology. But the job is only half done, according to Michael B. Wallace, MD, MPH, professor of medicine at Mayo Clinic, Jacksonville, FL.

“There is overwhelming data that getting a colonoscopy reduces your risk of death from colon cancer by about 50 percent,” Dr. Wallace said “And we have data showing that if you get a very high-quality colonoscopy, as measured by a high adenoma detection rate (ADR), you have a further 50 percent reduction in the risk of colorectal cancer. We also know that about 50 percent of so-called interval colon cancers are due to missed polyps. Colonoscopy is a success story, but we are only halfway there.”

Dr. Wallace will explore the latest data on techniques to improve ADR and better visualize difficult polyps during Sunday’s DDW Combined Clinical Symposium Colorectal Cancer Screening. The symposium is jointly sponsored by AGA, ASGE and SSAT. The session’s speakers, including Rajesh N. Keswani, MD, will cover topics ranging from bowel prep to laparoscopic management of malignant polyps.

“Bowel preparation is one of those critical elements that doesn’t get enough attention,” said Dr. Keswani, associate professor of medicine at the Northwestern University Feinberg School of Medicine, Chicago, IL. “The reality is that most of the colonoscopy procedure occurs before the patient gets to the endoscopy suite. Bowel preparation occurs at home, not under our direct supervision, and preparation is critical to the quality of colonoscopy.”

Split bowel preparation is a standard of care, Dr. Keswani noted, but there are exceptions based on the timing of colonoscopy. Patients with a late afternoon colonoscopy may benefit by completing the entire bowl preparation the morning of the procedure.

There are also groups that have modified the traditional recommendation that patients consume only clear liquids the day before colonoscopy, citing data that suggests a low-residue diet does not negatively impact preparation.

“Colonoscopy is a disruptive procedure for the patient,” Dr. Keswani said. “We want to do everything we can to make it as effective as we can. Not only does an impaired preparation lead to repeat procedures, it actually reduces the detection of polyps. Bowel preparation is a serious issue.”

Colonoscopy techniques are equally serious. The national benchmark for ADR is 25 percent, Dr. Wallace said, but current data suggests that high-quality colonoscopy yields an ADR of 33 percent or higher in average-risk populations.

“Our current goal is to achieve an ADR of 33 percent or higher,” he said. “Regular feedback — telling clinicians what their ADR is, what the goal should be and working with the practice to create a culture of quality — makes a difference. Our own endoscopic quality improvement program, or EQIP, has shown that simply being part of a formal quality-improvement program significantly increases ADR.”

Multiple studies point to five techniques that help improve detection rates:

  • Use of a high-definition endoscope.
  • Washing away residual liquid stool and mucus to improve visualization.
  • Use of tip deflecting to examine behind folds.
  • Performing a double exam of the right colon; either two forward views, or one forward and one in retroflection.
  • Adequately distending the colon, preferably with carbon dioxide.

“A longer inspection time — more than six of seven minutes — is associated with higher ADR,” Dr. Wallace said. “You can’t do a high-quality colonoscopy in three or four minutes. The way to keep costs down is not by doing a quick colonoscopy but to do a high-quality colonoscopy that prevents colon cancer. It is much more cost-effective to prevent a cancer than to miss it and pay for surgery and chemotherapy.”

Please refer to the DDW Mobile App or the schedule-at-a-glance on page 2 for the time and location of this and other DDW events.