Abstract: Objective To investigate the accuracy and influencing factors of endoscopic ultrasound for T-staging of early colorectal cancer. Methods A total of 186 patients (with 200 lesions) with early colorectal cancer who were hospitalized and underwent endoscopic resection at Beijing Friendship Hospital, Capital Medical University from September 2017 to June 2021 were included. The clinical information, pathological diagnosis, colonoscopy and endoscopic ultrasound manifestations were retrieved. The diagnostic efficacy of endoscopic ultrasound was analyzed with reference to pathological staging, and the factors affecting the accuracy of endoscopic ultrasound were analyzed by Logistic regression model. Results The overall accuracy of endoscopic ultrasound in diagnosing the depth of infiltration of early colorectal cancer was 75.0% (150/200), and the accuracy rates for intramucosal and submucosal infiltrating cancers were 85.0% and 35.0%, respectively. Univariate analysis showed that the diagnostic accuracy of endoscopic ultrasound was not related to lesion site, size, or morphology, but related to histologic type and lesion depth (P<0.001). Multivariate analysis showed that histologic type was a risk factor for misjudgment of depth, and the accuracy was significantly lower for moderately/poorly differentiated adenocarcinoma, mucinous adenocarcinoma or signet-ring cell carcinoma (P=0.019). Conclusion Endoscopic ultrasound is useful for determining the depth of infiltration in early colorectal cancer. However, the accuracy is reduced when the tumor has a moderately/poorly differentiated or undifferentiated component.

Key words: early colorectal cancer, endoscopic ultrasound, T-staging