Can Non-expert Physicians Use the Japan Narrow-band Imaging Expert Team Classification to Diagnose Colonic Polyps Effectively?

OBJECTIVES: In 2014, the Japan narrow-band imaging expert team (JNET) proposed the first unified colorectal narrow-band imaging magnifying classification system, the JNET classification. The clinical usefulness of this system has been well established in JNET member institutions, but its suitability for use by “non-expert physicians” (physicians with no expertise in the use of JNET classification) remains unclear. This study aimed to examine the clinical usefulness of the JNET classification by “non-expert physicians”. METHODS: We retrospectively analyzed 852 consecutive patients who underwent screening colonoscopy following a positive fecal occult blood test between January 2017 and May 2018. Endoscopic results from colon polyp diagnosis by physicians who started using the JNET classification (JNET group) were compared with those of physicians who did not (control group). Mann-Whitney U test and Fisher's exact test were used to compare continuous and categorical variables, respectively. RESULTS: The median patient age was 68 years, and the male-to-female ratio was 1:0.84. When no lesions were found, the median withdrawal time was significantly different between groups (JNET group: 12 min; control group: 15 min; P < 0.01). The number of resected adenomas per colonoscopy was significantly higher in the JNET group (1.7) than in the control group (1.2; P < 0.01). Among the resected lesions, 8.9% in the JNET group and 17% in the control group were non-neoplastic lesions that did not require resection (P < 0.01). CONCLUSIONS: Colon polyp diagnosis using the JNET classification can reduce unnecessary resection during magnifying colonoscopy when conducted by “non-expert physicians”.