Clin Endosc.  2017 May;50(3):279-286. 10.5946/ce.2016.107.

External Validation of the Endoscopic Features of Sessile Serrated Adenomas in Expert and Trainee Colonoscopists

• Yang HJ
• Lee JI
• Park SK
• Jung YS
• Sohn JH
• Choi KY
• Park DI

• KMID: 2388825
• DOI: http://doi.org/10.5946/ce.2016.107

Abstract

BACKGROUND/AIMS
It is unclear whether the endoscopic features of sessile serrated adenomas (SSAs) would be useful to trainee colonoscopists to predict SSA. Therefore, the present study aimed to identify features that expert and trainee colonoscopists can use to independently and reliably predict SSA by using high-resolution white-light endoscopy.
METHODS
Endoscopic images of 81 polyps (39 SSAs, 22 hyperplastic polyps, and 20 tubular adenomas) from 43 patients were retrospectively evaluated by 10 colonoscopists (four experts and six trainees). Eight endoscopic features of SSAs were assessed for each polyp.
RESULTS
According to multivariable analysis, a mucous cap (odds ratio [OR], 10.44; 95% confidence interval [CI], 5.72 to 19.07), indistinctive borders (OR, 4.21; 95% CI, 2.74 to 7.16), dark spots (OR, 3.64; 95% CI, 1.89 to 7.00), and cloud-like surface (OR, 2.43; 95% CI, 1.27 to 4.668) were independent predictors of SSAs. Among these, a mucous cap, indistinctive borders, and cloud-like surface showed moderate interobserver agreement (mean κ>0.40) among experts and trainees. When ≥1 of the three predictors was observed, the sensitivity and specificity for diagnosing SSAs were 79.0% and 81.4%, respectively.
CONCLUSIONS
Colonoscopy trainees and experts can use several specific endoscopic features to independently and reliably predict SSAs.

Keyword

Colorectal neoplasms; Colonoscopy; Sensitivity and specificity; Observer variation; Education, medical, graduate

MeSH Terms

Adenoma*
Colonoscopy
Colorectal Neoplasms
Education, Medical, Graduate
Endoscopy
Humans
Observer Variation
Polyps
Retrospective Studies
Sensitivity and Specificity

Figure

• 

  Fig. 1. Endoscopic features of sessile serrated adenoma (SSA). (A) A 6-mm SSA located in the proximal transverse colon showing a rim of debris, mucous cap, and absence of surface vessels. (B) A 15-mm SSA located in the cecum showing indistinctive borders (arrows), an irregular shape, and a cloud-like surface without surface vessels. (C) A 12-mm SSA located in the mid-ascending colon showing a rim of debris, indistinctive borders, and an irregular shape. (D) A 12-mm SSA located in the splenic flexure demonstrating the absence of surface vessels with indistinctive borders. (E) A 12-mm SSA with an irregular shape located in the cecum covered with a mucous cap on the nodular surface. (F) A 6-mm SSA located in the cecum showing dark spots inside the crypts in addition to an irregular shape and cloud-like surface. (G) A 15-mm SSA located in the proximal ascending colon with dark spots inside the crypts and the absence of surface vessels.

• 

  Fig. 2. Prevalence of individual endoscopic features of sessile serrated adenoma (SSAs) according to the histology of polyps among (A) colonoscopy experts and (B) trainees. All features were observed more frequently in SSAs than in non-SSAs by experts and trainees (p<0.01, all). HP, hyperplastic polyp; TA, tubular adenoma.

• 

  Fig. 3. The receiver-operating characteristic curves of the three independent predictive features with moderate interobserver agreement (mucous cap, indistinctive borders, and cloud-like surface) for discriminating (A) between sessile serrated adenomas (SSAs) and non-SSAs, and (B) between SSAs and hyperplastic polyps. AUROC, area under the receiver-operating characteristic curve.

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