title: Endoscopic appearance of proximal colorectal neoplasms and potential implications for colonoscopy in cancer prevention.
abstract: BACKGROUND
  In everyday practice, the use of colonoscopy for the prevention of colorectal cancer (CRC) is less effective in the proximal than the distal colon. A potential explanation for this is that proximal neoplasms have a more subtle endoscopic appearance, making them more likely to be overlooked.
  
  
  OBJECTIVE
  To investigate the differences in endoscopic appearance, ie, diminutive size and nonpolypoid shape, of proximal compared with distal colorectal neoplasms.
  
  
  METHODS
  Cross-sectional, single-center study.
  
  
  METHODS
  Endoscopists at the Maastricht University Medical Center in the Netherlands who were previously trained in the detection and classification of nonpolypoid colorectal lesions.
  
  
  METHODS
  Consecutive patients undergoing elective colonoscopy.
  
  
  METHODS
  Endoscopic appearance, ie, diminutive size (<6 mm) or nonpolypoid shape (height less than half of the diameter) of colorectal adenomas and serrated polyps (SPs), with a focus on adenomas with advanced histology, ie, high-grade dysplasia or early CRC and SPs with dysplasia or large size.
  
  
  RESULTS
  We included 3720 consecutive patients with 2106 adenomas and 941 SPs. We found that in both men and women, proximal adenomas with high-grade dysplasia/early CRC (n = 181) were more likely to be diminutive or nonpolypoid than distal ones (76.3% vs 26.2%; odds ratio [OR] 9.24; 95% CI, 4.45-19.2; P < .001). Of the proximal adenomas, 84.4% were diminutive or nonpolypoid compared with 68.0% of the distal ones (OR 2.66; 95% CI, 2.14-3.29; P < .001). Likewise, large/dysplastic SPs in the proximal colon were more often nonpolypoid than distal ones (66.2% vs 27.8%; OR 5.51; 95% CI, 2.79-10.9; P < .001).
  
  
  CONCLUSIONS
  Inclusion of both symptomatic and asymptomatic patients.
  
  
  CONCLUSIONS
  Proximal colorectal neoplasms with advanced histology frequently are small or have a nonpolypoid appearance. These findings support careful inspection of the proximal colon, if quality of cancer prevention with the use of colonoscopy is to be optimized.
authors.affiliation: Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Eveline J A
authors.initials: EJ
authors.lastname: Rondagh
authors.forename: Mariëlle W E
authors.initials: MW
authors.lastname: Bouwens
authors.forename: Robert G
authors.initials: RG
authors.lastname: Riedl
authors.forename: Bjorn
authors.initials: B
authors.lastname: Winkens
authors.forename: Rogier
authors.initials: R
authors.lastname: de Ridder
authors.forename: Tonya
authors.initials: T
authors.lastname: Kaltenbach
authors.forename: Roy M
authors.initials: RM
authors.lastname: Soetikno
authors.forename: Ad A M
authors.initials: AA
authors.lastname: Masclee
authors.forename: Silvia
authors.initials: S
authors.lastname: Sanduleanu
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D003106:Colon / Q000473:pathology; D044682:Colon, Ascending / Q000473:pathology; D044683:Colon, Descending / Q000473:pathology; D012809:Colon, Sigmoid / Q000473:pathology; D044684:Colon, Transverse / Q000473:pathology; D003111:Colonic Polyps / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000517:prevention & control; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged