Evaluation of endoscopic ultrasonography in colorectal villous lesions

Abstract

Background and aims. The choice of therapeutic procedure for colorectal neoplasias depends largely on the depth of tumor invasion. This study examined the value of endoscopic ultrasonography (EUS) in determining whether local resection is applicable for colorectal villous lesions.

Materials and methods. We performed EUS on 125 colorectal neoplasias classified into two categories, villous (n=35) and nonvillous lesions (n=90), according to their colonoscopic morphological features. We compared the EUS and clinicopathological findings for each lesion.

Results. The overall accuracy of EUS-based evaluation of tumor invasion depth was 60% in villous lesions and 91% in nonvillous lesions. In villous lesions 37% were overstaged and 3% understaged, and in of nonvillous lesions 6% were overstaged and 3% understaged. In differentiating mucosal neoplasias (M)/submucosal cancers with slight invasion (SM-s) from non-M/SM-s, the values in villous and nonvillous lesions were, respectively: sensitivity 60% and 86%, specificity 100% and 99%, and accuracy 66% and 96%. Large (≥20 mm wide, ≥5 mm high) or rectal villous lesions were more likely than nonvillous lesions to be misjudged with regard to the differentiation between M/SM-s and non-M/SM-s.

Conclusion. It is difficult to determine the depth of invasion in villous lesions, especially large or rectal lesions, using only EUS. EUS-based evaluation alone cannot determine the appropriate treatment for colorectal villous lesions.