Value Of 3-Dimensional Endorectal Ultrasonography In Evaluating T Staging And Circumferential Resection Margin Of Mid-low Rectal Cancer

Objective To compare the report of 3-dimensional endorectal ultrasonography（3D-ERUS）VS.2-dimensional endorectal ultrasonography （2D-ERUS）on T staging and circumferential resection margin（CRM）assessing in mid-low rectal cancer,and explore the value of 3D-ERUS in preoperative evaluation of T staging and circumferential resection margin（CRM）of mid-low rectal cancer.Methods Between August 2015 and September 2016,both 3D-ERUS and2D-ERUS were performed prior to surgery in 134 patients with histologically proven mid-low rectal cancer by the colonoscopic biopsy in the first Affiliated Hospital of Guangxi Medical University.The T staging and CRM were evaluated and compared with postoperative pathologic results.ResultsThe overall accuracy of 3D-ERUS and 2D-ERUS for T-staging were 88.8%and 79.1%,respectively.The accuracy of 3D-ERUS for T1-T2,T3,T4stages were 92.5%,91.8%and 93.3%.The accuracy of 2D-ERUS for T1-T2,T3,T4 stages were 88.8%,84.3%and 85.1%.The overall accuracy of3D-ERUS for T-staging was higher than that of 2D-ERUS,there was statistical difference between them（P_总=0.030）.The accuracy of 3D-ERUS for T4-staging was higher than that of 2D-ERUS,there was statistical difference between them（P₄=0.031）.The accuracy of 3D-ERUS for T1-T2,T3 stages were compared with that of 2D-ERUS,there were no statistical difference between them(P_1-2=0.294;P₃=0.060).The accuracy of 3D-ERUS and 2D-ERUS for CRM of T3-staging were 93.7%and 87.9%,there was no statistical difference between them（P=0.274）.The consistency of the results between 3D-ERUS and pathology was higher than that between 2D-ERUS and pathology（Kappa₁=0.822>Kappa₂=0.668;Kappa₃=0.632>Kappa₄=0.302）.Conclusion3D-ERUS can be used to accurately evaluate T-staging and CRM of mid-low rectal cancer.3D-ERUS has more superiority in T-staging especially T4-staging evaluation of mid-low rectal cancer.