Comparative Study Between Preoperative Staging By Transrectal Ultrasonography, Computerized Tomography And Postoperative Pathologic Findings In Rectal Cancer

Rectal adenocarcinoma is common cancer in china,and accounts for 60～75%of colorectal cancer.More and more studies have focused on prognostic factors and management of rectal cancer.The results of the present study demonstrated that a good excision or combined modality therapy can increase the chance for sphincter, bladder and sexual function evaluation of extension of tumor mass and local lymphatic spread is essential for successful treatment.At the present time,transrectal ultrasonography(TRUS)and computerized tomography(CT)have commonly used in preoperative staging.The aim of this series was to evaluate the accuracy of the CT imaging as compared with TRUS in detected the T and N stage by comparison with the pathologic findings.Material and methods1.Patients:Between November 2005 and July 2007,92 patients with positive biopsy of the rectum were investigated by TRUS and CT before operation at our surgery department.All patients were submitted to endoscopy prior to TRUS and CT.2.Technique of TRUS:a transrectal sonographic apparatus with 5～10MHZ probe which have two oriented scan plane(DU8 ultrasound systems,Esaote medical) was used.Then,the tumor and lymph nodes stage were indentified by ultrasonography.3.Technique of CT:A Lightspeed16 CT(GE medical)was used for all examination. Slices was taken after air inflation of the bowel.Then,the tumor and lymph nodes stage were indentified by CT imaging.4.Image assessment and classification:TRUS stage:uT1 tumors invade into but not through the submucosa,uT2 tumors invade into but not through the muscularis propria,uT3 tomors invade through the muscularis propria into sucubserosa,uT4 tumors invade other organs or structures.The perirectal nodes were considered involoved when≥5mm.CT stage:T1-2 tumors confined to the rectal wall.T3 extrarectal extension like as clubbed/wavy appearance or illegibility of perirectal fatty tissue.T4 tumors invade other organs or pelvic sidewall.The perirectal nodes were considered involoved when≥8mm.Histopathological stage according to the TNM classification(UICC 1997)5.Statistical analysis:All analysis were performed using SPSS11.5.Chi-square trend test were used to test the relationship between TRUS and CT imaging results.A value of p＜0.05 was considered statistically significant.Results1.Tumor penetration(T stage)The TRUS assessment an overall T,T1,T2,T3 and T4 stage revealed a accuracy of 87.0%(80/92),100%(3/3),81.5%(22/27),87.5%(42/48),92.9%(13/14), respectively.The accuracy of CT for overall T,T_1-2,T3 and T4 stage was 68.5%(63/92),63.3%(19/30),66.7%(32/48),85.7%(12/14),respectively.The accuracy of TRUS was superior to CT.(x²=9.07,P＜0.01).2.Lymph nodes stage(N stage)The assessment of N stage revealed a sensitivity,specificity,and accuracy 54.1%(20/37),70.9%(39/55),64.1%(59/92),respectively,for TRUS and 51.4%(19/37),76.4%(42/55),66.3%(61/92)for CT imaging.And,the different was not statistically significant.(x²=0.10,P＞0.05)ConclusionsTRUS and SCT are accurate in predicting the stage of bowel wall penetration in rectal cancer.Preoperative staging of tumor penetration is performed better with TRUS as compared with SCT.Because TRUS is cheap,simple and convenient,it can be as the first choice for preoperative staging in rectal carcinoma.Both methods are relatively inaccurate for lymph node staging.But it maybe better if both methods are used together.