Narrow-band imaging magnification predicts the histology and invasion depth of colorectal tumors

Abstract

Background: There are several reports concerning the differential diagnosis of non-neoplastic and neoplastic colorectal lesions by narrow-band imaging (NBI). However, there are only a few NBI articles that assessed invasion depth.

Objective: To determine the clinical usefulness of NBI magnification for evaluating microvessel architecture in relation to pit appearances and in the qualitative diagnosis of colorectal tumors.

Design: A retrospective study.

Setting: Department of Endoscopy, Hiroshima University, Hiroshima, Japan.

Patients and main outcome measurements: A total of 289 colorectal lesions were analyzed: 12 hyperplasias (HP), 165 tubular adenomas (TA), 65 carcinomas with intramucosal to scanty submucosal invasion (M-SM-s), and 47 carcinomas with massive submucosal invasion (SM-m). Lesions were observed by NBI magnifying endoscopy and were classified according to microvessel features and pit appearances: type A, type B, and type C. Type C was divided into 3 subtypes (C1, C2, and C3), according to the detailed NBI magnifying findings of pit visibility, vessel diameter, irregularity, and distribution. These were compared with histologic findings.

Results: Histologic findings of HP and TA were seen in 80.0% and 20.0%, respectively, of type A lesions. TA and M-SM-s were found in 79.7% and 20.3%, respectively, of type B lesions. TA, M-SM-s, and SM-m were found in 21.6%, 29.9%, and 48.5, respectively, of type C lesions. HPs were observed significantly more often than TAs in type A lesions, TAs were observed significantly more often than carcinomas in type B lesions, carcinomas were observed significantly more often than TAs in type C (P < .01). TA, M-SM-s, and SM-m were found in 46.7%, 42.2%, and 11.1% of type C1 lesions, respectively. M-SM-s and SM-m were found in 45.5% and 54.5%, respectively, of type C2 lesions. SM-m was found in 100% of type C3 lesions. TAs and M-SM-s were observed significantly more often than SM-m in type C1 lesions, and SM-m were observed significantly more often than TAs and M-SM-s in type C3 lesions (P < .01).

Conclusions: NBI magnification findings of colorectal lesions were associated with histologic grade and invasion depth.