[Utility of the capilar pattern in the NBI diagnosis of superficial lesions of the colon: prospective validation in a private endoscopic center Lima, Peru].

Introduction: It is important to detect and remove adenomas in order to prevent colon cancer. Angiogenesis is an early change in the pre malignant transformation sequence and narrow band imaging (NBI) allows for better visualization of the capillary pattern of the mucosa.

Objective: We present our data regarding the assessment of superficial lesions of the colon on colonoscopies using NBI as well as the Sano-Emura classification.

Materials & Methods: Prospective study done in Lima Peru. Three endoscopists evaluate the capillary pattern of colonic lesions in real time using NBI and electronic magnification. These findings are then compared to the pathology report.

Results: 380 patients were evaluated with a total of 739 lesions; 473 adenomas, 241 non neoplastic lesions, and 25 serrated lesions. These were grouped depending on their NBI capillary pattern into two groups: Neoplastic (Sano-Emura types II, IIIa, and IIIb), and Non-Neoplastic (Sano-Emura type I). Sensitivity for adenomas 84%, diagnostic accuracy 77%, PPV 82%, NPV 67%, specificity 63%. Sensitivity and diagnostic accuracy improved to 94% and 84%, respectively when evaluating lesions of 5 mm to 9 mm. For diminutive rectosigmoid polyps, the NPV for adenomas was 81%. The serrated lesions showed both types of capillary pattern with equal frequency.

Conclusions: Our results using NBI with electronic magnification showed that this method is useful for the differentiation of lesions 5 mm or bigger, as reported previously. Accuracy was diminished when evaluating lesions less than 5 mm. NBI was not capable of aiding in the differential diagnosis of serrated lesions.