[The value of transrectal sonography and computerized tomography in the diagnosis of rectal cancer]

In a prospective study in 49 patients with rectal carcinoma the correlation of pre- and postoperative staging by CT and endorectal ultrasound was proven according to TNM-classification. With CT the pre/postoperative results correlated in T1 in 9/10, in T2 in 10/16, in T3 in 13/15 and in T4 in 6/8 patients. By endorectal ultrasound identical results were found in all T1, in 10/12 T2, in 17/20 T3 and in 6/7 T4 stages. Totally, pre- and postoperative identical results were found by CT in 38 and by endorectal ultrasound in 43/49 patients. Overestimation of the tumor stage was similar with both methods: 5 by CT and 4 by endorectal ultrasound. Underestimation of the stage was more often by CT with 5 than by endorectal ultrasound with 2 cases (CT: accuracy 77.5%, sensitivity 88.3%, specificity 94.4%; endorectal ultrasound: accuracy 87.7%, sensitivity 91.5%, specificity 97.8%). Criteria for interpretation are discussed. In early tumor stages the depth of tumor invasion can be better evaluated by endorectal ultrasound. In late stages both methods give important information for the surgical strategy.