The value of endorectal ultrasound in the assessment of adenomas, T1- and T2-carcinomas.

In a prospective study we examined the value of endorectal ultrasound (ERUS) in the preoperative staging of potentially locally excisable tumours. During the study period from 1.1.1991 to 1.3.1996 a total of 160 rectal tumours in 152 patients were staged endosonographically (uT/uN) and compared postoperatively with the histologic result (pT/pN) at the University Hospital of Würzburg. Thirty-eight (24%) patients had an adenoma and 15 (9%) a T1-carcinoma. In 29 (18%) cases a T2-cancer was diagnosed, further 67 (42%) and 11 (7%) patients presented with a T3 and T4 tumour, respectively. The sensitivity for adenomas and T1-Ca (uT0/1) was 81%, the specificity 98%. For T2 tumours, the sensitivity was only 41% and the specificity 92% as the majority (17 of 29) of pT2 neoplasias were overstaged (uT3). The overall staging accuracy (T1-4) was 77.5%. Two patients with a pT1-Ca and seven with a pT2-Ca had lymph node metastases which were detected preoperatively in five. The accuracy for lymph node staging was 83%. We conclude that adenomas and T1 tumours can be assessed with a high grade of accuracy using ERUS. In these tumours ERUS can be used to assist clinical decision-making (transanal vs. abdominal operation). Owing to the lack of sensitivity ERUS is of no help in the assessment of T2 carcinomas.