Endorectal ultrasonography for the assessment of invasion of rectal tumours and lymph node involvement.

Sophisticated therapies for rectal carcinoma, such as sphincter preserving operations, pouch-anal anastomosis, preoperative irradiation or adjuvant chemotherapy, require an exact pretherapy assessment of the tumour and its lymph node involvement. A 7.0 MHz transducer was used before operation in the staging of 117 patients with rectal carcinoma or villous adenoma. In 90 per cent of cases it was possible correctly to stage the tumour before operation. Sensitivity for detection of perirectal fat infiltration was 97 per cent. Lymph node involvement was accurately identified in about 80 per cent of cases. Six carcinomas, which had developed within 31 examined tubulovillous adenomas, were detected by endorectal ultrasonography. No carcinoma remained undetected. Endorectal ultrasonography is a highly accurate tool for the staging of rectal carcinoma before operation and for the detection of lymph node involvement. Malignant change in tubulovillous adenomas are also detectable.