Feasibility and accuracy of TRUS in the pre-treatment staging for rectal carcinoma in general practice

Transrectal ultrasonography (TRUS) is the diagnostic tool of choice for local staging of rectal carcinoma. The accuracy in determining of tumour infiltration depth has been reported to reach 95% (on average, 85%). The aim of the study was to analyse the diagnostic accuracy of the TRUS in the clinical routine.

From 01/01/2000 to 12/31/2003, all patients with rectal carcinoma were enrolled in a prospective multicenter observational study. In case of complete findings of pre-operative TRUS and post-operative histological investigation of the surgical specimen on the tumour infiltration depth, overall accuracy of TRUS was determined.

Overall, 13,610 patients with rectal carcinoma were enrolled in the study. Five thousand and fifty-six subjects (37%) underwent TRUS. In 3,501 patients, TRUS finding (uT-stage) could be compared with the result of the definitive histologic investigation (pT-stage). The accuracy of TRUS in all T-stages was 65.8%. The highest sensitivity was achieved in the T3-stage (74.9%), while in T2, T1, and T4, it was 59.6, 59.0 and 31.1%, respectively. In discriminating tumour growth limited to the rectal wall vs that through the rectal wall into the neighboring tissue, TRUS-associated accuracy was 76.5%. There were no differences between various tumour locations above the anocutaneous line.

Diagnostic accuracy of TRUS in determining depth of tumour infiltration within or through the rectum wall in the routinuous diagnostic of rectal carcinoma does not reach the excellent published study results. A considerable improvement of the qualitative outcome in using this specific diagnostic tool appears to be recommendable to utilize its advantages such as high accuracy, efficacy, and practicability in the diagnostic process and deriving consequences for a possible neoadjuvant treatment as well as optimal planning of the surgical approach.