Clinical Usefulness of Prostate Specific Antigen and Prostate Specific Antigen Density to Distinguish Benign from Malignant Prostate Diseases

Abstract

The possibility of distinguishing prostate cancer from BPH with the prostate specific antigen (PSA) determination is particularly poor when PSA levels are between 4.1 and 10 ng/ml. In these cases the quotient of serum PSA and prostate volume, defined as prostate specific antigen density (PSAD), seems to enhance the accuracy of PSA alone. In this study we evaluated retrospectively the preoperative PSA levels in 139 patients with BPH and in 26 patients with prostate cancer who underwent surgical treatment at our Department. We calculated the prostate volume with the following formula: length x width x depth x 0.52. The three dimensions were obtained from the surgical specimen in the patients with prostate cancer and using transrectal ultrasound in the cases of BPH. In patients with a serum PSA level of 4.1 to 10 ng/ml, PSA alone was not able to distinguish benign from malignant prostate disease; the PSAD values, on the contrary, provided a statistically significant (p < 0.003) stratification between BPH and prostate cancer (mean PSAD of 0.0088 and 0.191 respectively). Only 6% of patients with BPH had a PSAD greater than 0.15 compared to 76% of patients with prostate cancer. These results suggest the usefulness of PSAD in predicting the presence of prostate cancer in patients with intermediate levels of serum PSA.