PSA and staging of localized prostate cancer.

Numerous studies have demonstrated a direct relationship between serum PSA and tumor volume. However, because of a substantial overlap between serum PSA concentrations and advancing clinical and pathologic stages, serum PSA has been found to be unreliable for predicting the final pathologic stage in an individual patient. Nevertheless, by combining various other preoperative measures such as clinical stage, biopsy grade, or both, several investigators have determined that the predictive power of serum PSA for pathologic stage can be significantly enhanced. Explanations for the failure of the serum PSA concentration alone to be useful in predicting final pathologic stage include the unpredictable contribution from the BPH component of the gland and the decreasing production of serum PSA by higher-grade lesions with increasing tumor volume.