SAN DIEGO, California — A balloon colonoscope increases the detection rate of polyps and adenomas compared with standard colonoscopy (SC), catching numerous polyps and adenomas that SC missed when conducted in sequence.

Current methods "miss up to 28% of polyps and 12% to 24% of adenomas, due to their location behind proximal fold, or because the lesions are flat, or [because of inadequate] bowel preparation," Seth Gross, MD, assistant professor of medicine at the New York University Langone Medical Center in New York City, said during his presentation of the research here at the American College of Gastroenterology (ACG) 2013 Annual Scientific Meeting and Postgraduate Course.

One potential tool to increase detection is NaviAid G-EYE, a balloon-colonoscope made by Smart Medical Systems. The device is a standard colonoscope with an integrated balloon at its distal tip. It requires no preprocedure preparation or mounting. The pressure within the balloon can be preset or user-selectable. The device is inserted with balloon deflated until it reaches the cecum, when the balloon is inflated to low pressure. The device is then withdrawn with the balloon inflated, and the intestinal folds are straightened, which smoothes the colon surface and improves visibility.

The researchers conducted a prospective, multicenter, randomized, tandem study in which 112 consecutive patients referred for colonoscopy were randomly assigned to receive a SC followed by G-EYE colonoscopy (GEC, group A) or GEC followed by SC (group B). All polyps were removed.

Table. Comparison of GEC and SC

  Group A (n = 56) Group B (n = 56)
First pass (SC) Second pass (GEC) Additional detection First pass (GEC) Second pass (SC) Additional detection
Polyps            
 2 to 5 mm 19 23 121% 26 3 11.5%
 5 to 10 mm; >10 mm 8; 3 5; 2 63%; 67% 7; 10 0; 0 0%; 0%
 Total 30 30 100% 43 3 7%
Adenomas            
 2 to 5 mm 10 10 100% 9 1 11.1%
 5 to 10 mm; >10 mm 6; 2 3; 1 50%; 50% 5; 10 0 0%; 0%
 Total 18 14 78% 24 1 4.2%

When GEC followed SC (group A), the researchers noted additional detection rates of 100% and 78% for polyps and adenomas, respectively. When SC followed GEC (group B), the additional detection rates were 7% and 4.2% for polyps and adenomas, respectively.

The additional detection rate ratio (the ratio of GEC second-pass additional detection and GEC first-pass miss rate) for the balloon colonoscope was 14.3 for polyps and 18.7 for adenomas.

Previous tandem studies of rear-viewing optics give an additional detection rate ratio of 1.5 for TER (Avantis Medical) and 8.9 for FUSE (EndoChoice).

"Compared to some of the other colonoscopy techniques such as FUSE, [the balloon-colonoscope] is slightly ahead," Dr. Gross said. He added that the researchers are conducting another study with a larger sample size.

Improved detection rates are encouraging, and the technique seems to be simple and cost-effective, according to Sushovan Guha, MD, PhD, an associate professor of gastroenterology, hepatology, and nutrition at the University of Texas Medical School at Houston, who attended the presentation.

However, the comparison of the balloon technique with SC is flawed, and the study had a relatively short withdrawal time. "The ideal should be to [compare] a standard colonoscope with a cap or another mechanical device vs the balloon so that you are comparing apples and apples," Dr. Guha told Medscape Medical News.

The fact that the device had success in detecting adenomas was encouraging. "Any system which will improve our adenoma detection rate will be immensely helpful, especially with 25% being nationally reported as the average miss rate. We should really get it down to 15% or less, as these are the [lesions] that are probably developing into cancer," Dr. Guha said.

In recent years, there has been an increase in the number of colorectal cancers that develop between screenings, which has led some to suggest a shortening of screening intervals. However, Dr. Guha does not agree with that approach. "We don't have the manpower to do it, so we should really look for a good examination [technique]," he said.

Mechanical devices and optical devices both have the potential to improve these rates, but Dr. Guha favors mechanical approaches. "With the FUSE technique, you need 3 screens. I [think] the mechanical adaptors will be much more advantageous than the optical [ones], because optical [systems] are more expensive, require some learning curve, and you need special scopes. It also increases the withdrawal time. The mechanical [approaches] are routinely used and people are familiar with them, they're cost-effective, and they don't need special scopes," said Dr. Guha.

Dr. Gross and Dr. Guha have disclosed no relevant financial relationships.

American College of Gastroenterology (ACG) 2013 Annual Scientific Meeting and Postgraduate Course: Abstract 21. Presented October 15, 2013.

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