Rectal endosonography accurately predicts depth of penetration in rectal cancer.

Sixty-three patients with primary rectal adenocarcinomas have been examined prior to surgery with rectal endosonography (ES). Maximum depths of tumour penetration measured endosonographically have been compared with subsequent maximum depths measured on the fixed resected specimen (n = 30) and the histological slide (n = 61). In both cases there was a good degree of correlation between the ultrasonic estimations of depth and the histological ones (r = 0.36, p = 0.05, CI = 95% and r = 0.46, p less than 0.001, CI = 99% respectively). In 12 cases ultrasonic depths of tumour were also measured in the laboratory and then compared with depths from fixed (n = 12) and fresh specimens (n = 5) with a good correlation (r = 0.75, p = 0.005, CI = 99% and r = 0.79, p = 0.036, CI = 95% respectively). Rectal endosonographic estimation of rectal cancer depth of invasion is an accurate measure of tumour penetration and may help distinguish between fixation due to inflammatory tissue and tumour fixity.