When performed by experienced colonoscopists, high-definition white-light endoscopy was found to be an acceptable alternative to pancolonic chromoendoscopy in detecting clinically relevant lesions in patients under surveillance for Lynch syndrome, according to a study published in Gastroenterology.

Dye-based pancolonic chromoendoscopy is currently recommended for detecting adenomas in patients with Lynch syndrome. However, there is few reports to support its superiority to high-definition white-light endoscopy.  Thus, the investigators of this randomized, parallel-controlled, prospective study assessed whether high-definition, white-light endoscopy is noninferior to dye-based pancolonic chromoendoscopy.

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The study included 256 adults with proven pathogenic germline variants in DNA mismatch repair genes, who were all under surveillance for Lynch syndrome at 14 centers across Spain from July 2016 to January 2018. Participants were randomly assigned to high-definition white-light endoscopy (n=128) or pancolonic chromoendoscopy (n=128) performed by 24 experienced high-detector endoscopists specializing in the screening of colorectal lesions in high-risk patients.


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The primary outcome was the rate of adenoma detection compared between groups. Rate of serrated lesion detection and polyp detection were also assessed. Subanalyses were performed to measure detection rates for flat adenomas, right-sided adenomas, advanced adenomas, serrated lesions of 5 mm or larger, lesions with proximal location to the splenic flexure, and sessile serrated lesions. The investigators assumed a relative margin of noninferiority defined as a maximum 15% difference in rates between surveillance techniques.

Overall, adenoma detection rates did not differ significantly between the pancolonic chromoendoscopy (34.4%; 95% CI, 26.4-43.3) and white-light endoscopy groups (28.1%; 95% CI, 21.1-36.4; P =.28) with an absolute difference of 5.5%. Serrated lesions were detected in a significantly higher percentage of patients undergoing pancolonic chromoendoscopy (37.5%; 95% CI, 29.5-46.1) vs white-light endoscopy (23.4%; 95% CI, 16.9-31.4; P =.01). Similarly, polyp detection rates were significantly higher in the pancolonic chromoendoscopy group (67.2%; 95% CI, 58.6-75.2) vs the white-light endoscopy group (50.0%; 95% CI, 41.5-58.5; P =.01). However, in detecting serrated lesions of 5 mm or larger, there was no significant difference between the pancolonic chromoendoscopy and white-light endoscopy groups (9.4% vs 7.0%; P =.49), nor were there significant differences in the detection of lesions of proximal location (11.7% vs 10.2%; P =.68) or sessile serrated lesions (3.9% vs 5.5%; P =.55). Total procedure times and withdrawal times were significantly longer in pancolonic chromoendoscopy compared with white-light endoscopy (30.7±12.8 minutes vs 22.4±8.7 minutes total procedure time, 18.3±7.6 minutes vs 13.5±5.6 minutes withdrawal time; P <.001).

Limitations to the study included the strictly controlled specialist setting, which may prevent the generalizability of results on the use of high-definition white-light endoscopy as a standard of care, and that the participating endoscopists were not blinded to the technique, potentially leading to observer bias.

The investigators suggest that high-definition white-light endoscopy, performed by experienced and dedicated endoscopists, may be an acceptable alternative to pancolonic chromoendoscopy for the detection of adenomas in patients under surveillance for Lynch syndrome. Although pancolonic chromoendoscopy was more time-consuming and detected more clinically irrelevant lesions, it should not be replaced by white-light endoscopy when only standard-definition technology is available or when used in low-detector hands.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference          

Rivero-Sanchez L, Arnau-Collell C, Herrero J, et al. White-light endoscopy is adequate for lynch syndrome surveillance in a randomized and non-inferiority study [published online September 11, 2019]. Gastroenterology. doi: 10.1053/j.gastro.2019.09.003