Impact of 2 generational improvements of colonoscopes on adenoma miss rates: results of a prospective randomized multicenter tandem study

Numerous randomized studies have shown that changing certain features of colonoscopes, usually incorporated when switching from one endoscope generation to the next, mostly do not increase adenoma yield. There is, however, indirect evidence that it may be necessary to skip one instrument generation (ie, changing from one generation to the next but one) to achieve this effect. We compared the latest-generation colonoscopes from one company (Olympus Exera III, 190-C) with the next to last one (Olympus 160/5-C) in a prospective multicenter study randomized for the order of colonoscopes in a tandem fashion, involving 2 different examiners. Patients with increased risk for colorectal neoplasia undergoing colonoscopy (FOBT positive, personal/familial history of CRC/adenoma, rectal bleeding, recent change in bowel movements) were included. Primary outcome was the adenoma miss rate with 190 (190-C) in comparison to 160/5 colonoscopes (160/5-C). 856 patients (48.8%male, mean age 58.3 years) with personal (41%) or family (38%) history of colorectal neoplasia, rectal bleeding (19%) and other indications were included. Of the 429 patients in the 190-C first group, 16.6% (95% CI, 13.0 % - 20.1%) had at least one adenoma missed during the first procedure, as compared with 30.2% (95% CI, 25.9% - 34.6%) in the group with 160/5-C first (p <0.001). Similarly, adenoma detection rate during the first colonoscopy was 43.8% versus 36.5% (p=0.030) for 190-C versus 160/5160/5-C, respectively. This randomized tandem trial showed lower adenoma miss rates and higher adenomas detection rates for the newer 190-colonoscopes compared with the 160/5-series. These results suggest that it takes multiple improvements such as those implemented over 2 instrument generations before an effect on adenoma (miss) rate can be observed