METHODS: We enrolled patients undergoing colonoscopy from February 2015 to May 2017 in two institutions. All procedures were performed with the latest system (EVIS LUCERA ELITE, Olympus). The cecum and ascending colon were first observed with white light imaging (WLI) in both the NBI and WLI group. Then, the colonoscope was re-inserted, and the cecum and ascending colon were observed for an additional 30 s. In this second observation, NBI was performed for the first 130 patients in the NBI group and WLI for the next 130 in the WLI group. The number of adenoma and sessile serrated polyps (ASPs) in the second observation were examined in both groups. According to our initial pilot study, the sample size was estimated at 126.
RESULTS: In the first observation, the number of ASPs was 72 in the NBI group and 72 in the WLI group (p = 1.0). In the second observation, the number of ASPs was 23 in the NBI group and 10 in the WLI group (p = 0.02). The polyp and adenoma detection rates in the second observation were 16.2% and 12.3% in the NBI group and 7.7% (p = 0.03) and 6.2% (p = 0.09) in the WLI group.
CONCLUSIONS: The additional 30-s observation with recent NBI decreased missed polyps in the right-sided colon.
METHODS: This was a multicenter retrospective-cohort study. We collected HGD and T1 lesions of ≤ 10 mm resected by CSP among 15 520 patients receiving CSP from 2014 to 2019 at nine related institutions, and we extracted only cases receiving definite follow-up colonoscopy after CSP of HGD and T1 lesions. We analyzed these tumor's characteristics and therapeutic results such as R0 resection and local recurrence and risk factors of recurrence.
RESULTS: We collected 103 patients (0.63%) and extracted 80 lesions in 74 patients receiving follow-up colonoscopy for CSP scar. Mean age was 68.4 ± 12.0, and male rate was 68.9% (51/80). The mean tumor size (mm) was 6.6 ± 2.5, and the rate of polypoid morphology and rectum location was 77.5% and 25.0%. The rate of magnified observation was 53.8%. The rates of en bloc resection and R0 resection were 92.5% and 37.5%. The local recurrence rate was 6.3% (5/80, median follow-up period: 24.0 months). The recurrence developed within 3 months after CSP for four out of five recurrent cases. Comparing five recurrent lesions to 75 non-recurrent lesions, a positive horizontal margin was a significant risk factor (60.0% vs 10.7%, P