Value of High Frequency Endoscopic Ultrasound Mini Probe in Pre-Operative TN Staging of Colorectal Cancer

Objective:To evaluate the value of high frequency endoscopy ultrasound(EUS) mini probe in the pre-operative TN staging of colorectal cancer.Methods:Colorectal cancers proved by colonoscopies and biopsies in 145 patients were preoperatively evaluated with high frequency endoscopic ultrasound mini probes to determine the depth of tumor invasion(T) and local lymph node metastasis(N) in order to estimate the accuracy of TN staging.The accuracy of T staging and tumor-node staging of colorectal cancer by EUS with high frequency mini probe was compared with post-operative pathologic findings.Results:The concordant diagnosis rates of T and N staging by endoscopic ultrasonography with high frequency mini probe and pathological findings were 84.83%and 70.34%,respectively.The concordance rates of T1,T2,T3 and T4 staging were 88.89%,85.71%, 4.27%and 80.00%,respectively.The concordance rates of EUS with high frequency mini probe in determining the stage lymph node metastasis(LNM) were 98.41%(LNM positive) and 92.68%(LNM negative);N1 and N2 staging were 76.92% and 16.22%,respectively.Conclusions:High frequency endoscopic ultrasound mini probe in the preoperative T staging for patients with colorectal cancer was relatively high,especially for early stage colorectal cancer and those with tumor stenosis;but its accuracy in determining the N2 staging needs to be modified.