Kinetic analysis of prostatic volume in treating prostatic cancer and its predictability for prognosis.

Prostatic volume in patients with prostatic cancer diminished remarkably after castration according to measurements by transrectal sonography. These kinetic changes in prostatic volume were analyzed and a formula was applied to the regression curve. The reduction time (tau) in the formula, which is a constant representing the time interval required for the effective portion of the prostate to be reduced to one tenth, was thought to be a good index to predict the prognosis of the patients.