The role of high-magnification-chromoscopic colonoscopy in hereditary nonpolyposis colorectal cancer screening: a prospective "back-to-back" endoscopic study

Am J Gastroenterol. 2005 Oct;100(10):2167-73. doi: 10.1111/j.1572-0241.2005.41481.x.


Background: In hereditary nonpolyposis colorectal cancer flat and diminutive adenomas occur, particularly in the right colon. Such lesions may assume a high risk of malignant transformation. Interval cancers are known to occur in this group. Chromoscopic colonoscopy enhances detection in patients assuming a moderate to high lifetime risk of colorectal cancer.

Aim: To prospectively assess the efficacy of high-magnification-chromoscopic colonoscopy for the detection of neoplastic lesions in patients undergoing hereditary nonpolyposis colorectal cancer screening.

Methods: Twenty-five asymptomatic patients fulfilling modified Amsterdam criteria underwent "back-to-back" colonoscopy. Conventional colonoscopy with targeted chromoscopy was performed initially followed by pan-colonic chromoscopic colonoscopy. Diagnostic extubation times and volumes of normal saline and indigo carmine (IC) were controlled.

Results: Using conventional colonoscopy and targeted chromoscopy 24 lesions were detected in 13 patients (20 exophytic/4 flat). Pan-colonic chromoscopy identified a further 52 lesions in 16 patients (17 exophytic/35 flat). Pan-chromoscopy identified significantly more adenomas than conventional colonoscopy (p= 0.001) and a significantly high number of flat adenomas (p= 0.004).

Conclusions: Pan-colonic chromoscopic colonoscopy improves detection of significant neoplastic lesions in hereditary nonpolyposis colorectal cancer screening. Pan-chromoscopy may help better stratify colorectal cancer "risk" in this cohort and aid planning of surveillance colonoscopic follow-up.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Colonoscopy / methods*
  • Colorectal Neoplasms, Hereditary Nonpolyposis / pathology*
  • Coloring Agents
  • Female
  • Humans
  • Indigo Carmine
  • Male
  • Middle Aged
  • Prospective Studies
  • Reproducibility of Results
  • Sensitivity and Specificity


  • Coloring Agents
  • Indigo Carmine