title: Risk factors associated with missed colorectal flat adenoma: a multicenter retrospective tandem colonoscopy study.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xiang
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhan
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Zhao
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Ya-Dong
authors.initials: YD
authors.lastname: Wang
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Sheng-Li
authors.initials: SL
authors.lastname: An
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Yang-Zhi
authors.initials: YZ
authors.lastname: Xu
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Li
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Gong
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Fa-Chao
authors.initials: FC
authors.lastname: Zhi
authors.affiliation: Li Xiang, Qiang Zhan, Xin-Hua Zhao, Ya-Dong Wang, Yang-Zhi Xu, Ai-Min Li, Wei Gong, Yang Bai, Fa-Chao Zhi, Si-De Liu, Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510000, Guangdong Province, China.
authors.forename: Si-De
authors.initials: SD
authors.lastname: Liu
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000328:Adult; D000367:Age Factors; D000368:Aged; D016009:Chi-Square Distribution; D002681:China; D002983:Clinical Competence; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology*; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D047368:Tumor Burden
keywords: Colonoscopy; Colorectal cancer; Flat adenoma; Miss rate; Risk factor