Three-camera endoscopy improves IBD dysplasia surveillance

Last Updated: 2017-02-08

By Scott Baltic

NEW YORK (Reuters Health) - Compared with conventional forward-viewing colonoscopy alone, adding the panoramic views obtained by full-spectrum endoscopy (FUSE) significantly reduced the risk that dysplastic lesions would be missed in patients with inflammatory bowel diseases (IBD), new research shows.

The FUSE device provides a 330-degree field of view that’s displayed on a triple-screen video monitor, allowing improved visualization of the side walls, blind spots and behind folds. In addition, FUSE is compatible with chromoendoscopy.

Colorectal cancer risk in patients with IBD is double that of the general population, with one in 14 patients developing such cancer after 30 years of IBD, the Australian researchers noted in a report online January 23 in Gastroenterology.

“Better dysplasia identification can therefore contribute toward colorectal cancer prevention and prolong surveillance intervals,” they said.

“Sporadic dysplasias develop in non-IBD subjects (and also in IBD) and are three-dimensional with more distinct margins. (These) polyps are relatively easy to see on standard colonoscopy,” co-author Dr. Rupert Leong of the University of Sydney told Reuters Health by email.

In contrast, he added, “IBD-associated dysplasias are driven by chronic inflammation and have different molecular pathways of cancer development. They are typically flat, lack definite edges and are sometimes completely invisible,” in which case they are found only when random non-targeted biopsies are taken.

For a randomized crossover study, they recruited 29 patients with ulcerative colitis and 23 with Crohn’s disease. The median age was 45, 60% were male, and the mean IBD duration was 16.4 years.

In random order, participants underwent FUSE colonoscopy and conventional colonoscopy with a current-generation forward-viewing colonoscope (FVC) with a 170-degree field of view.

The first colonoscopy of the two was performed with white-light illumination on insertion and on withdrawal. The second colonoscopy was performed with white-light illumination on insertion and segmental dye-spray chromoendoscopy (using methylene blue 0.1%) on withdrawal from the cecum.

During withdrawal in the second colonoscopy, two random biopsies were taken from every bowel segment after inspection of the corresponding dye-sprayed segment.

In all, 28 dysplastic lesions were identified in 16 subjects, of whom eight received FVC first and 8 received FUSE first. The total dysplasia prevalence rate was 30.8%.

Thirteen (46.4%) dysplastic lesions were identified on the first-pass colonoscopy, three (10.7%) on the second-pass white-light colonoscopy on insertion, 10 (37.7%) flat dysplastic lesions on chromoendoscopy on withdrawal, and two (7.1%) by random biopsies.

On a per-lesion basis, FVC missed 71.4% of dysplastic lesions, while FUSE missed 25.0% (p=0.0001). Per-patient results were similar.

“Although FUSE performed better than FVC, both instruments missed dysplastic lesions on white light inspection alone,” the report noted.

Chromoendoscopy identified seven unique subjects (13.5% of participants) with dysplasia missed on white light inspection by FUSE and FVC, leading the authors to write that “FUSE does not replace chromoendoscopy and the two techniques are complementary.”

Further, according to the report, “IBD surveillance procedures using FUSE with chromoendoscopy may permit lengthening of colonoscopy surveillance intervals and provide patients and clinicians with greater reassurance of negative findings.”

In an email to Reuters Health, Dr. Tonya Kaltenbach, of the University of California, San Francisco School of Medicine and the San Francisco Veterans Affairs Medical Center, highlighted the study’s small size and its high incidence of dysplasia, 19 of 52 (36.5%). In her research group’s synthesis of prior studies, she said, the prevalence of dysplasia in a mixed IBD population was about 10%.

The miss rate of both high-definition technologies using white light alone was also noteworthy, Dr. Kaltenbach said. “Most dysplastic lesions identified were flat in morphology, and 56% of subjects with dysplasia required chromoendoscopy for dysplasia detection.”

“This finding highlights the limitations of high-definition technology alone and the need for chromoendoscopy to optimize dysplasia detection,” Kaltenbach said. Even when more of the colon’s surface area can be seen with wide-angle technology, she added, the use of dye is needed to enhance the contrast of subtle, often flat dysplastic lesions.

Dr. Leong received an unrestricted investigator-initiated research grant from EndoChoice, the manufacturer of the three-camera colonoscope used in the study. The sponsor had no role in trial design, execution, data analysis, interpretation, the decision to submit the paper or manuscript preparation.

SOURCE: http://bit.ly/2kP1Fe6

Gastroenterology 2017.