Widespread application of dye to the lumen of the colon (pan-chromoendoscopy) improves the detection
of diminutive lesions (Brown, Baraza & Hurlstone 2007) (I). However, pan-chromoendoscopy is
time consuming and the extra lesions detected may be unimportant clinically as a significant number
of diminutive lesions may regress (Rother, Knopfle & Bohndorf 2007). The authors of a recent Cochrane
review concluded that selective application of dye to suspicious areas (selective chromoendoscopy)
may be more appropriate during colonoscopy
This approach is consistent with the conclusions of a recent international workshop which reviewed
the role of non-polypoid lesions in the aetiology of colorectal cancer. The endoscopist should be skilled
in recognising subtle changes in the appearance of the mucosal surface, particularly alterations in colour,
vascularisation and morphology, to identify suspicious areas requiring dye spraying and to better
detect polypoid lesions. Small patches of mucus may require rinsing to expose underlying suspicious
areas worthy of staining, particularly in the right colon
Selective chromoendoscopy with dye spraying on the lesion has been shown to be superior to conventional
colonoscopy predicting polyp histology (Pohl et al. 2008) (III). Magnification chromoendoscopy
is more effective than conventional chromocolonoscopy for diagnosing neoplastic colorectal
polyps (Emura et al. 2007)
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