[Intrarectal ultrasonography in the preoperative assessment of the depth of infiltration of rectal tumors].

From June 1987 to February 1990, 142 out of 319 patients with rectal tumours were investigated by ultrasound scanning with the object of ascertaining the depth to which the tumour had infiltrated. This examination proved completely feasible in 130 of these patients (84 men, 46 women, mean age 61.7 [42-84] years). Postoperative histological examination revealed an adenoma (n = 59) or a T1 carcinoma (n = 19), while intrarectal ultrasonography disclosed the same findings in 79 patients (true-positive in 75 cases). A T2-tumour was diagnosed by histological examination in 24 patients, and by ultrasonography in 22 (true-positive in 18 cases). The histological diagnosis of a tumour in stage T3 or T4 (n = 27) was in close agreement with the ultrasound findings (n = 24). The positive predictive value of ultrasonography ranged between 0.94 and 0.97 depending on the staging of the tumour, and the sensitivity between 0.75 and 0.96. Preoperative ultrasonographic determination of the depth of invasion of a rectal tumour enables the surgeon to devise a therapeutic plan to suit the individual patient's needs; one option may be local excision.