Staging of Early Colorectal Cancers: Magnifying Colonoscopy versus Endoscopic Ultrasonography for Estimation of Depth of Invasion

Background and aims Preoperative estimation of depth of invasion in early colorectal cancers (CRCs) is essential for patient management. This study was conducted to compare the diagnostic accuracies of magnifying colonoscopy and endoscopic ultrasonography (EUS) for estimating the depth of invasion of early CRCs. Subjects and methods A total of 438 early CRCs were removed endoscopically or surgically from July 1993 through March 1999 at our hospital. Before removal, 102 lesions were evaluated with both magnifying colonoscopy and EUS and were included in this analysis. The diagnostic accuracy of each method, referring to the histology of the resected specimens, was evaluated. Results The overall diagnostic accuracies were 87% (89/102) for magnifying colonoscopy and 75% (76/102) for EUS (P = 0.0985). Subgroup analysis was also done for polypoid and non-polypoid lesions. For polypoid lesions, the overall diagnostic accuracies of magnifying colonoscopy and EUS were 88% (60/68) and 72% (49/68), (P = 0.0785), and for non-polypoid lesions, they were 85% (29/34) and 79% (27/34), (P = 0.7169). Conclusion Although, there is a substantial difference in the overall diagnostic accuracies, it is not statistically significant. Therefore, we conclude that magnifying colonoscopy is at least as accurate as EUS for preoperative staging of early CRCs.