Background: The aim of this prospective study is to compare the usefulness of magnifying narrow band imaging (NBI) and magnifying chromoendoscopy in the diagnosis of colorectal lesions.
Methods: The subjects were 1185 patients who underwent a complete colonoscopic examination and endoscopic or surgical treatment, from January 2006 to February 2008. A total of 1473 lesions were evaluated (53 hyperplastic polyps, 1317 adenomas, 103 submucosally invasive cancers). The digital images with NBI or chromoendoscopy were recorded and diagnosed independently from each other by two endoscopists who were blinded to the final pathological diagnosis.
Results: We could differentiate between neoplastic and non-neoplastic lesions with sensitivity of 88.9%, specificity of 98.5% and accuracy of 98.2% according to the vascular pattern. By recognizing an irregular or sparse pattern with NBI, massively invasive submucosal cancer could be diagnosed with the sensitivity and specificity of 94.9% and 76.0%. Using chromoendoscopy, we could differentiate between neoplastic and non-neoplastic lesions with sensitivity of 86.8% and specificity of 99.2%. We were able to differentiate between massively invasive cancers and slightly invasive cancers using the pit patterns with sensitivity of 89.7% and specificity of 88.0%. The specificity was superior to that of NBI colonoscopy.
Conclusion: Both NBI and chromoendoscopy can be useful for distinguishing between neoplastic and non-neoplastic lesions. In the diagnosis of submucosal cancer, pit pattern diagnosis was slightly superior to vascular pattern diagnosis. It is desirable to perform chromoendoscopy in addition to NBI for distinguishing between slightly and massively invasive submucosal cancer lesions and determining the treatment.