Accuracy of digital rectal examination in the estimation of height of rectal lesions

Abstract

To assess the accuracy of the digital rectal examination as a method of estimating the distance of a rectal lesion from the anal verge. One hundred doctors of variable levels of experience and from different specialities performed digital rectal examination (DRE) on a pelvic model with two fixed buttons at different levels simulating lesions in the rectum. They were asked to estimate the distance of the lesions in centimetres from the anal verge and classify the lesion as mid or low rectal. Nearly half the doctors studied (45%) estimated the distance of the upper lesion accurately (7.5 cm, or within 1 cm of the correct distance), whereas 64% of the doctors estimated the distance to the lower lesion accurately (3 cm, or within 1 cm of correct distance). 93% of doctors classified the mid-rectal lesion correctly and 99% classified the lower rectal lesion correctly. Though less accurate in precisely estimating the distance of a lesion from the anal verge, DRE has high accuracy in classifying rectal lesions into lower and mid-rectal lesions, irrespective of experience and background of the clinicians. It is more accurate for lower rectal lesions than mid-rectal lesions.