Magnifying chromoendoscopy and endoscopic ultrasonography measure invasion depth of early stage colorectal cancer with equal accuracy on the basis of a prospective trial.

Background & Aims: Magnifying chromoendoscopy (MC) and endoscopic ultrasonography (EUS) are used to estimate the depth of colorectal cancer (CRC) invasion, but it is not clear which procedure is more accurate. We performed a prospective study to compare MC and EUS.

Methods: A total of 70 patients with an early stage flat CRC lesion were enrolled at 6 institutions in Japan and randomly assigned to groups assessed by MC followed by EUS or EUS followed by MC. Results from MC and EUS measurements of 66 lesions were included in the final analysis. The invasion depth of each lesion was measured by each procedure and categorized as mucosal to slight submucosal (depth <1000 μm) or deep submucosal (depth ≥ 1000 μm); measurements were compared with the final diagnosis on the basis of the pathology analysis. All participating examiners achieved a mean κ value ≥ 0.6 for both MC and EUS before this trial.

Results: MC and EUS each measured the depth of lesion invasion with 71.2% accuracy (correctly for 47 of 66 lesions). MC identified lesions with deep submucosal invasion with 74.2% sensitivity and 68.6% specificity, whereas EUS identified them with 67.7% sensitivity and 74.3% specificity. The differences between MC and EUS measurements did not differ significantly. However, MC required significantly shorter observation time than EUS (361.7 ± 164.5 seconds vs 451.2 ± 209.4 seconds, P = .002).

Conclusions: MC and EUS are equally accurate in estimating the invasion depth of early stage CRC lesions. However, neither procedure has sufficient diagnostic accuracy to be used as the standard. University Hospital Medical Network Clinical Trials Registry, Number: UMIN 000005085.