Routine use of transrectal ultrasound in rectal carcinoma: results of a prospective multicenter study

Preoperative transrectal ultrasound (TRUS) can establish the depth of penetration of a tumor, and thus provide important information for decisions about further management. In the literature, this method is reported to have a high level of sensitivity and specificity. Our investigation aimed at establishing the quality of the diagnostic procedure and treatment of colorectal carcinoma.

This investigation, which covered a 1-year period, and involved 75 hospitals, was conducted in the form of a prospective multicenter study and included a total of 3756 patients. For rectal carcinomas, all endosonographically determined uT categories were compared with histologically established T categories (pT).

At 49 hospitals a total of 499 TRUS examinations in 1463 rectal carcinomas (34.1 %) were performed. A comparison of uT with pT category was possible for 422 TRUS examinations. Agreement between the preoperative endosonographic diagnosis with the histological diagnosis was found in 63.3 % (n = 267) of cases (95 % confidence interval 58.5 % - 67.9 %). The diagnostic accuracy was 50.8 % for pT1 carcinomas, 58.3 % for pT2 lesions, 73.5 % for pT3 tumors, and 44.4 % for pT4 carcinomas. Overstaging was observed in 23.9 %, overall, and understaging in 12.8 %. Understaging was significantly less common than overstaging (P < 0.05, s.).

The accuracy of transrectal ultrasound used as a routine clinical examination in rectal carcinoma patients was clearly lower than that reported in the literature. We conclude that TRUS may aid decisions relevant to treatment only when used by well-trained investigators with a large case load of rectal carcinoma patients. Centralization of transrectal ultrasonography service is mandatory if a high level of quality is to be achieved with this method.