Assessment of volume measurement of the prostate using per-rectal ultrasonography.

A study was made of 100 cadaveric prostates (71 benign glands and 29 invaded by adenocarcinoma) using a technique that enabled per-rectal ultrasonography to be carried out and their volumes measured by computed planimetry. These volumes were compared directly with the actual volumes of the glands measured after dissection from the cadaver specimens. A high degree of correlation was obtained for the measurement of benign glands (r = 0.982) and glands containing cancers confined within the capsule (r = 0.961). Estimation of the size of cancers unconfined to the gland was poor and measurement was not possible with 3 malignant prostates that had extended beyond the prostatic capsule so that the ultrasonic boundary could not be defined.