LAUSR

Colonoscopic screening and surveillance programs have been implemented in many countries and they have reduced colorectal cancer (CRC)-related deaths. However, this reduction was significantly noted in distal CRC, not in proximal CRC, and some patients may develop unexpected CRC within 3–5 years of colonoscopy. Interval CRCs, which have a prevalence ranging from 1.8% to 9.0%, are CRCs that are diagnosed after a screening or surveillance examination and before the date of the next recommended exam. It is known that interval CRCs are more common in the proximal colon than in the distal colon. Research regarding the molecular profiles of interval CRCs and serrated lesions have identified a molecular similarity between the interval CRCs and the pathway for serrated adenoma carcinogenesis. Due to the sessile or flat features associated with these lesions, preference for right colon and molecular features of sessile serrated adenomas/polyps (SSA/Ps), SSA/Ps have been getting attention for their clinical importance in interval CRCs. Despite advancement in imaging systems and some known endoscopic features characteristic of SSA/Ps, the detection and accurate identification of SSA/Ps during colonoscopy is challenging to the colonoscopist. In this issue of Clinical Endoscopy, Yang et al. validated previously reported endoscopic features of SSA/Ps and identified features that can be reliably used for SSA/P prediction by experts and trainees. The endoscopic features of SSA/Ps in this study are: indistinct borders, irregular shape, rim of debris, cloud-like surface, mucous cap, nodular surface, absence of surface vessels, and dark spots. Among these eight features, four included independent predictive features for SSA/P histology (indistinctive borders, mucous cap, cloudlike surface and dark spots). Additionally, three of these four features showed moderate interobserver agreement among experts and trainees (the exception being dark sports). These three characteristics rendered 79.0% sensitivity and 81.4% specificity for SSA prediction using high resolution white light endoscopy. With regards to the method of this study, I noticed an interesting point. Yang et al. held a training session and consensus meeting before the validation of the endoscopic features. This process might be the major reason why the interobserver agreement among trainees was not inferior to that of experts. Therefore, setting up courses that include a training session and consensus meeting might be helpful for trainees, not only for SSA/Ps but also for other lesions. Although the suitable degree of interobserver agreement in trainees in this study could not be applied to other medical centers which have not set-up the courses, the three simple endoscopic features could easily be used and prove to be helpful for colonoscopy training elsewhere. Received: April 1, 2017 Accepted: April 26, 2017 Correspondence: Suk Pyo Shin Department of Internal Medicine, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, 77 sakju-ro, Chuncheon 24253, Korea Tel: +82-33-240-5823, Fax: +82-33-255-4291, E-mail: [email protected]