Three-dimensional and endoscopic ultrasonography miniprobes in the pre-operative staging of rectal cancer

Introduction: Miniprobe (MP) EUS and threedimensional (3D) EUS are two new endo-rectal techniques that stand to not only replace conventional (conv) techniques but also improve staging (st) of rectal carcinoma (RC). Aims: carry out pre-operative evaluations of RC using EUS MP and 3D EUS and compare results with conv EUS assessments and pathological st. Material: 60 patients with RC studied. 3 types of equipment used for EUS: conv EUS (GF-UM20), 12MHz MP (UM-2R), and 3D EUS (Easy 3D Freescan). Comparisons among 3 techniques and between these and pathology results. Patients divided into 2 groups: those who had not undergone pre-operative adjuvant therapy and those who had. For first group we compared results obtained with MP and 3D imaging against conv EUS and pathology findings. With second group we compared results obtained with MP and 3D imaging against those obtained using conv EUS (gold standard). We verified if longi. or circu. extent of lesion had any influence on accuracy (ac) of the different techniques of T and N st. Results: T st, concordance (co) between MP and conv EUS was significant (K=0.81; p<0.001), as was co between 3D and conv EUS (K=0.87; p<0.001). Same was ascertained in co between pathology data and: conv EUS (K=0.81; p<0.001; ac 85.2%), MP EUS (K=0.76; p<0.001; ac 81.5%) and 3D EUS (K=0.95; p<0.001; ac 96.3%). N st, co between MP and conv EUS was significant (K=0.61; p<0.001), as was co between 3D and conv EUS (K=0.70; p<0.001). Same was ascertained in co between pathology data and: conv EUS (K=0.80; p<0.001; ac 90.5%, sensi 77.8%), MP EUS (K=0.59; p<0.003; ac 81%, sensi 55.6%) and 3D EUS (K=1; p<0.001; ac 100%, sensi 100%). Speci 100% for all 3 techniques. T and N st ac for the 3 techniques was not influenced by longi. or circu. extent of tumour. Conclusion: MP and 3D EUS proved to be valid in staging of RC. 3D EUS showed greater concordance with pathological st.