The role of prostatic planimetry using transrectal sonography in prostatic diseases

Transrectal sonography (TRS) remains the best method for prostatic planimetry, providing much information of value for the diagnosis and treatment of prostatic diseases, particularly of prostatic cancer. Currently, TRS is a routine tool in the detection and treatment of prostatic cancer. Prostatic planimetry is also available for a better understanding of elevated prostate-specific antigen (PSA). PSA indices modified by prostatic volume are applicable to the detection of prostatic cancer. The most critical application of prostatic planimetry is in monitoring prostatic cancer after treatment. Prostatic volume decreased exponentially after androgen deprivation therapy without exception in patients with prostatic cancer. The parameter "tau" (Tau), calculated from kinetic analysis based on sequential planimetric volumetry using TRS after the initiation of treatment, is a reliable prognosticator in an individual patient. Furthermore, tau predicts the manner of disease progression, and local or metastatic progression. Thus, transrectal ultrasonic prostatic planimetry is of special value in prostatic cancer.