Accuracy of digital palpation for size assessment of the prostate evaluated by transrectal sonography.

In order to clarify how precisely digital palpation gives information on prostatic size, evaluation of the size measurement of the prostate by means of transrectal sonography was performed on 1,543 subjects with various prostatic disorders. There was little agreement between the assessment of prostatic size by digital palpation and the ultrasonic measurement. The larger the prostate the less accurate was digital palpation. The prostatic size assessed by digital palpation was particularly dispersed widely in the prostate of 'hen's egg' size. It was proved that the size assessment by digital palpation was only effective statistically in a two-step differentiation, 'hen's egg' size and smaller. More complicated size classification was of little clinical value in digital palpation.