Risk factors associated with the detection and missed diagnosis of colorectal flat adenoma: a Chinese multicenter observational study.

OBJECTIVES: Flat colorectal adenomas have a high risk of malignancy; however, their detection is often difficult due to their flat morphology. In this retrospective, large-scale study, we investigated the prevalence and characteristics of flat adenomas in a population in China. METHODS: We analyzed the data collected for 16951 consecutive patients who underwent colonoscopy at four participating hospitals between September 2013 and September 2015. All colonoscopies were performed without magnification. RESULTS: Among the 1,6951 patients, 2938 (17.3%) had adenoma and 796 (4.7%) had flat adenomas. The detection of flat adenoma showed a weak correlation with the detection of adenoma (r = 0.666). Multivariable logistic regression analysis revealed the following independent factors influencing the detection of flat adenomas: patient-related factors of age, presence of warning symptoms, history of adenomas and bowel preparation as well as endoscopist-related factors of endoscopist's level of proficiency, number of colonoscopy operators and withdrawal time. CONCLUSIONS: The prevalence of flat adenomas in our study on Chinese patients was consistent with that reported from other countries. Factors conducive to the detection of flat adenomas were patient age of > 60 years, warning symptoms, history of adenoma, good bowel preparation, experienced endoscopist, single-operator colonoscopy and colonoscopy withdrawal time of >6 min.

Value of the patency capsule in pre-evaluation for capsule endoscopy in cases of intestinal obstruction.

OBJECTIVE: Patency capsule (PC) is a tool to screen the patency of the gastrointestinal (GI) tract. Capsule endoscopy can be performed after the patency is confirmed by the patency capsule. We aimed to estimate the diagnostic value of PC based on the existing trials. METHODS: We searched PubMed, CENTRAL and EMBASE for studies that included patients with suspected small bowel stricture who were evaluated by both PC and a reference standard (following capsule endoscopy and/or surgical pathology and/or endoscopic findings) and who were eligible for inclusion. The quality of the eligible studies was assessed using the Quality Assessment for Diagnostic Accuracy Studies-2 criteria. Sensitivity, specificity, likelihood ratios and the area under the receiver operating characteristic curve (AUROC) were calculated. RESULTS: Five studies including 203 patients fulfilled the eligibility criteria. The pooled data showed a PC sensitivity of 97% (95% CI 93-99%) and a specificity of 83% (95% CI 65-94%). The AUROC was 0.9557. CONCLUSIONS: PC may be of diagnostic value in confirming the patency of the GI tract before capsule endoscopy. The routine use of PC might eliminate the contraindication of capsule endoscopy in many cases of intestinal obstruction.

Risk factors associated with missed colorectal flat adenoma: a multicenter retrospective tandem colonoscopy study.

AIM: To determine the miss rate for colorectal flat adenomas during colonoscopy and the risk factors. METHODS: Flat adenomas are frequently missed during colonoscopy. However, the risk factors that influence their miss rates are unclear. This was a multicenter, retrospective study in which patients diagnosed with colorectal adenomas at a diagnostic colonoscopy and followed within 3 mo by a second therapeutic colonoscopy were pooled out from the established database. The "per-patient" and "per-adenoma" adenoma miss rates (AMR) for overall adenomas and flat adenomas, and patient-, adenoma-, and procedure-related risk factors potentially associated with the "per-adenoma" AMR for flat adenomas were determined. RESULTS: Chromoscopy and high-definition colonoscopy were not taken under consideration in the study. Among 2093 patients with colorectal adenomas, 691 (33.0%) were diagnosed with flat adenomas, 514 with concomitant protruding adenomas and 177 without. The "per-patient" AMR for flat adenomas was 43.3% (299/691); the rates were 54.3% and 11.3%, respectively, for those with protruding adenomas and those without (OR = 9.320, 95%CI: 5.672-15.314, χ (2) = 99.084, P < 0.001). The "per-adenoma" AMR for flat adenomas was 44.3% (406/916). In multivariate analysis, older age, presence of concomitant protruding adenomas, poor bowel preparation, smaller adenoma size, location at the right colon, insufficient experience of the colonoscopist, and withdrawal time < 6 min were associated with an increased "per-adenoma" AMR for flat adenomas. The AMR for flat adenomas was moderately correlated with that for overall adenomas (r = 0.516, P < 0.0001). The AMR for flat adenomas during colonoscopy was high. CONCLUSION: Patient's age, concomitant protruding adenomas, bowel preparation, size and location of adenomas, proficiency of the colonoscopist, and withdrawal time are factors affecting the "per-adenoma" AMR for flat adenomas.