Accuracy for optical diagnosis of small colorectal polyps in nonacademic settings

When small colorectal lesions are accurately characterized, adenomas can be removed and discarded without formal histopathology analysis. Previous studies in an academic setting showed that many lesions can be managed accurately on the basis of their endoscopic image (optical diagnosis). We performed a prospective study to assess the accuracy of optical diagnosis of small colorectal polyps in a nonacademic setting (the DISCOUNT trial) by using high-resolution endoscopy (HRE) and narrow-band imaging (NBI).

During colonoscopy, 1 of 3 nonacademic endoscopists characterized small lesions and declared whether this was done with low or high confidence. In cases of high confidence, the endoscopists decided whether lesions should be removed and discarded or whether they could be left in situ. A surveillance interval was then recommended on-site.

Of 215 patients in the study, 108 were found to have 281 small lesions. Of these lesions, 231 were characterized with high confidence by using HRE or NBI; the level of corresponding sensitivity was 77.0% (95% confidence interval, 68.4-83.8), and specificity was 78.8% (95% confidence interval, 70.6-85.2). Of these lesions, 164 were assigned for removal, and 67 were assigned to remain in situ, including 9 adenomas. In 54 patients, a surveillance interval could be recommended on-site that was in line with Dutch guidelines for 44 patients.

Even though many lesions were characterized by HRE or NBI with high confidence, optical diagnosis in a nonacademic setting proved to be disappointing, with a sensitivity of 77.0% and a specificity of 78.8%. Many lesions were accurately assigned to be removed or remain in situ, although few adenomas were assigned to remain in situ. Also, 19% of on-site recommendations for a surveillance interval proved to be inaccurate.