Linked Color Imaging for the Detection of Polyps, Adenomas in Lynch Syndrome

Study data published in Gut suggest that linked color imaging (LCI) may improve adenoma detection in patients with Lynch syndrome. In a trial which compared LCI to standard high-definition white light endoscopy (HD-WLI), LCI was associated with an increase in the number of polyps detected per patient and an improved adenoma detection rate. However, LCI did not appear to improve the proportion of patients with at least 1 polyp detected.

LCI is an enhanced imaging technique designed to improve the detection rate of polyps and adenomas during colonoscopy. While patients with Lynch syndrome undergo routine colonoscopic surveillance, interval cancer rates remain high. To assess the potential capacity of LCI to improve colorectal cancer detection in patients with Lynch syndrome, investigators performed a prospective, randomized controlled trial at 8 centers in Belgium, Italy, the Netherlands, Poland, Spain, and the United Kingdom.

Between January 2018 and March 2020, the study enrolled consecutive adult patients with Lynch syndrome who were undergoing routine colonoscopic surveillance. Patients were randomized 1:1 to receive inspection with either LCI or HD-WLI.

The primary outcome was polyp detection rate, defined as the number of patients with at least 1 polyp detected. Secondary measures included adenoma detection rate, mean number of polyps and adenomas detected, and median procedure time. Relative risk ratios (RR) were calculated for dichotomous outcomes; incidence rate ratios (IRRs) were used for continuous outcomes. Analyses were stratified by endoscopy center.

The study cohort consisted of 332 patients: 160 in the LCI arm and 172 in the HD-WLI arm. Demographic characteristics were comparable between groups. The overall polyp detection rate was 40.1% (95% confidence interval [CI], 34.7-45.6%). Polyp detection rate was not significantly higher with LCI (44.4%; 95% CI, 36.5-52.4%) compared with HD-WLE (36.0%; 95% CI, 28.9-43.7%) (RR, 1.23; 95% CI, 0.95-1.60, P =.12). However, the overall adenoma detection rate was elevated with LCI (36.3%; 95% CI, 28.8-44.2%) vs HD-WLE (25.6%; 95% CI, 19.2%-32.9%) (RR, 1.42; 95% CI, 1.02-1.96; P =.04).

The mean number of polyps per patient was significantly higher with LCI compared with HD-WLE (0.94 ± 1.40 vs 0.62 ± 1.14) (IRR, 1.51; 95% CI, 1.05-2.16; P =.03). The mean number of detected adenomas per patient was also greater with LCI vs HD-WLE (0.65 ± 1.11 vs 0.42 ± 0.92) (IRR, 1.55; 95% CI, 1.02-2.35; P =.04).

Regarding specific adenoma types, significantly greater proportions of the LCI vs HD-WLE arms had proximal adenomas (28.1% vs 18.6%; P =.04) and ≤5 mm adenomas (32.5% vs 22.1%; P =.03). However, detection rates for advanced adenoma and carcinoma were not different between groups. Median procedure and withdrawal times were also comparable between groups.

Per these data, LCI may be an important surveillance tool for patients with Lynch syndrome. Clinically significant increases in number of detected polyps and adenomas were observed compared to HD-WLE.

As far as study limitations, investigators cited the use of multiple study centers, across which procedures were not standardized. Additionally, participating endoscopists were highly experienced, and thus results may not be generalizable to less specialized clinics. 

“[I]n this randomised controlled trial performed in an expert setting, LCI did not increase the proportion of patients with at least one polyp detected compared with HD- WLE in patients with Lynch syndrome,” investigators wrote. “However, since LCI improved adenoma detection without additional withdrawal time or additional costs, it might still be valuable for surveillance of patients with Lynch syndrome.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry.

Please see the original reference for a full list of authors’ disclosures.

Reference

Houwen BBSL, Hazewinkel Y, Pellisé M, et al. Linked colour imaging for the detection of polyps in patients with Lynch syndrome: a multicentre, parallel randomised controlled trial. Gut. Published online March 18, 2021. doi: 10.1136/gutjnl-2020-323132