The Calculus of Serum PSA.

OBJECTIVES

To review the mathematics of kinetic changes in serum prostate-specific antigen (PSA) and to use a compartmental model to derive a new kinetic measure, alpha.

METHODS

The calculus of kinetic measures of PSA changes with time is presented, and a compartmental model is then used to derive alpha of serum PSA. Alpha is then tested for prognostic importance in 119 men who underwent prostatectomy.

RESULTS

The percentage of tumor in the prostate is closely related to alpha and to tumor length in diagnostic needle biopsies, but not to tumor grade. The presence of adverse pathology in the prostatectomy specimens (positive margins or T3 stage) is significantly associated with alpha, but not to tumor length or grade.

CONCLUSIONS

The derived kinetic parameter, alpha, shows promise as a preoperative prognostic parameter, and may help sort patients into those with low vs high probability for adverse pathology features in the prostatectomy specimens.