Endoscopic appearance of proximal colorectal neoplasms and potential implications for colonoscopy in cancer prevention

Gastrointest Endosc. 2012 Jun;75(6):1218-25. doi: 10.1016/j.gie.2012.02.010. Epub 2012 Apr 5.


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.

Design: Cross-sectional, single-center study.

Setting: Endoscopists at the Maastricht University Medical Center in the Netherlands who were previously trained in the detection and classification of nonpolypoid colorectal lesions.

Patients: Consecutive patients undergoing elective colonoscopy.

Main outcome measurements: 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).

Limitations: 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.

MeSH terms

  • Adenoma / pathology*
  • Adult
  • Aged
  • Chi-Square Distribution
  • Colon / pathology
  • Colon, Ascending / pathology
  • Colon, Descending / pathology
  • Colon, Sigmoid / pathology
  • Colon, Transverse / pathology
  • Colonic Polyps / pathology*
  • Colonoscopy*
  • Colorectal Neoplasms / pathology*
  • Colorectal Neoplasms / prevention & control
  • Cross-Sectional Studies
  • Female
  • Humans
  • Logistic Models
  • Male
  • Middle Aged