Retrospective Cohort Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 14, 2017; 23(42): 7609-7617
Published online Nov 14, 2017. doi: 10.3748/wjg.v23.i42.7609
Post-colonoscopy colorectal cancer rate in the era of high-definition colonoscopy
Mineo Iwatate, Tomoyuki Kitagawa, Yasumi Katayama, Naohiko Tokutomi, Shinichi Ban, Santa Hattori, Noriaki Hasuike, Wataru Sano, Yasushi Sano, Masaya Tamano
Mineo Iwatate, Santa Hattori, Noriaki Hasuike, Wataru Sano, Yasushi Sano, Gastrointestinal Center and Institute of Minimally-Invasive Endoscopic Care, Sano Hospital, Kobe, Hyogo 655-0031, Japan
Mineo Iwatate, Tomoyuki Kitagawa, Yasumi Katayama, Naohiko Tokutomi, Masaya Tamano, Department of Gastroenterology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama 343-8555, Japan
Shinichi Ban, Department of Pathology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama 343-8555, Japan
Author contributions: Iwatate M, Katayama Y, Sano Y and Tamano M contributed to study concept and design; Iwatate M, Kitagawa T, Katayama Y, Tokutomi N, Ban S, Hattori S, Hasuike N, Sano W and Sano Y contributed to acquisition and analysis of data; Iwatate M drafted the manuscript; Katayama Y, Ban S, Sano Y and Tamano M critically revised the manuscript for intellectual content.
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board at Sano Hospital and Dokkyo Medical University Koshigaya Hospital.
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous data that were obtained after each patient agreed to colonoscopy or surgery by written consent.
Conflict-of-interest statement: The authors have no conflicts of interest to declare in relation to this study.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Mineo Iwatate, MD, Gastrointestinal Center and Institute of Minimally-Invasive Endoscopic Care, Sano Hospital, 2-5-1 Shimizugaoka, Tarumi-ku, Kobe, Hyogo 655-0031, Japan. m.iwatate15@gmail.com
Telephone: +81-78-7851000 Fax: +81-78-7850077
Received: August 30, 2017
Peer-review started: August 31, 2017
First decision: September 20, 2017
Revised: October 2, 2017
Accepted: October 26, 2017
Article in press: October 26, 2017
Published online: November 14, 2017
ARTICLE HIGHLIGHTS
Research background

Post-colonoscopy colorectal cancers (PCCRC) has been recognized as a key quality indicator for colonoscopy. The data of PCCRC has been reported from Western counties, however that from Asian countries is lacking. Theoretically, HD colonoscopy has the potential to reduce the incidence of PCCRC, but clinical data related to this issue are still insufficient.

Research motivation

The PCCRC rate at two academic centers might help to set a benchmark for the quality of colonoscopy in Asian countries, where data on PCCRC are scarce.

Research objectives

To investigate the PCCRC rate for HD colonoscopy compared with that for standard-definition colonoscopy reported previously.

Research methods

We retrospectively examined the medical records of consecutive adult patients with CRC between 2010 and 2015 at Sano Hospital (SH) and Dokkyo Medical University Koshigaya Hospital (DMUKH) in Japan. Patients with CRC diagnosed within 6 to 36 mo of HD colonoscopy were classified as a PCCCRC group, and the others as a non-PCCRC group. The primary outcome was the PCCRC rate with HD colonoscopy. The secondary outcomes were factors associated with PCCRC and possible reason for occurrence of early and advanced PCCRC.

Research results

We analyzed 851 patients with 892 CRCs including 11 of PCCRC and 881 of non-PCCRC. The PCCRC rate was 1.7% (8/471) at SH and 0.7% (3/421) at DMUKH. Factors significantly associated with PCCRC were smaller size, a shallower invasion depth, a non-polypoid macroscopic appearance, and an earlier stage. The leading possible reason was non-polypoid shape for early PCCRC and blinded location for advanced PCCRC.

Research conclusions

We demonstrated the lower PCCRC rate for high-definition colonoscopy compared for standard-definition colonoscopy reported previously (0.7%-1.7% vs 1.8%-9.0%). Technological advance from standard-definition to high-definition colonoscopy has the potential to reduce the incidence of PCCRC.

Research perspectives

Early PCCRC may be missed by inconspicuous macroscopic type, and advanced PCCRC by the position in blinded location. Endoscopists should be aware that even large advanced CRC can be easily missed during colonoscopy. We should learn the reason why we missed CRC during colonoscopy and prevent the PCCRC in the future. The development of accessory devices and new modalities are expected to improve observation in “blind” areas of the colon and decrease the PCCRC.