Application of Utrasonic Probe for Preoperative Staging of Rectal Cancer

Objective:To evaluate the accuracy of T and N staging for rectal cancer and the usage of preoperative staging with endoscopic ultrasound probe retrospectively.Methods:The endoscopic ultrasound probe(12 MHz) was used in this study and fifty-three patients with carcinoma of rectum underwent endoscopic ultrasonography(EUS) with this probe.The diagnosing of tumor invasion(T staging) and local lymphatic node metastasis(N staging) was compared with result of operations research and histological stage(pT and pN) of these patients.Accuracy of T staging,sensitive and specificity of N staging were evaluated.Results:The accuracy rate of T staging was 79.2% with this probe.T staging accuracy rate for early stage rectal cancer was 100% and 75.0% for advanced tumors(pT2-pT4) respectively.It was not affected by the tumor location,sharp of tumors,tumor invasive area of rectal wall and body mass index(BMI) of patients.The accuracy,sensitivity and specificity of N staging were 65.1%,20.0% and 89.3% respectively.Conclusions:EUS can accurately assess T stage of rectal cancer although N staging remaines suboptimal.This is a useful and reliable method for preoperative T staging especially in diagnosing early stage rectal cancer.