Intrarectal ultrasound and computed tomography in the pre- and postoperative assessment of patients with rectal cancer.

The ability of intrarectal ultrasound to recognize the local extent of disease was investigated in 23 patients with histologically proven adenocarcinoma of the lower two-thirds of the rectum before operation. Two probes, 12 cm long, working at a frequency of 3.5 and 7.5 MHz, were used. The results were compared with those of pre-operative computed tomography (CT) and with the pathological report of the resected specimens. Sonography correctly staged 20 of 23 tumours with two false negatives and one false positive, while CT correctly staged 19 of 23 tumours with two false negatives and two false positives. The results of ultrasound were found to be as accurate as those of CT; the low cost and simple use of ultrasound makes it preferable in the pre-operative assessment of the depth of invasion of rectal cancer. In addition, intrarectal ultrasound was routinely performed in 42 patients, operated on for rectal cancer by means of sphincter-saving procedures, at variable intervals in the first 2 years postoperatively. Eight local recurrences were recognized and confirmed by CT. Based on the low cost, reliability and simple use, intrarectal ultrasound is proposed as first examination for local recurrence detection in the follow-up of patients with low anterior resection for rectal cancer.