Prostate-specific antigen density: correlation with histological diagnosis of prostate cancer, benign prostatic hyperplasia and prostatitis.

OBJECTIVE

To assess the additional value of prostate-specific antigen density in the diagnosis of prostate cancer in patients who undergo prostate biopsies.

PATIENTS AND METHODS

The study comprised 376 patients with symptoms of prostatism who were undergoing prostate biopsy. Digital rectal examination (DRE) and transrectal ultrasonography (TRUS) were performed and the prostate specific antigen level (PSA) and density (PSAD) were determined for each patient.

RESULTS

Both PSA and PSAD significantly differentiated (P < 0.001) between benign and malignant histology. Of the 376 patients, 91 (24%) had a PSA level in the intermediate range (4.0-10.0 ng/mL). In these patients PSAD was significantly better than PSA in differentiating between benign and malignant histology (P = 0.027 vs 0.316). With a PSAD limit of 0.15 ng/mL/cm3 in these patients, the sensitivity was 92% and the specificity was 54% for the diagnosis of prostate cancer. No patient with a positive biopsy had a PSAD < 0.11 ng/mL/cm3. No limiting value could be found for PSAD that combined both an acceptable sensitivity and specificity. Of the patients with a malignancy detected by the biopsy, 92% also had a suspect DRE.

CONCLUSION

In patients with intermediate PSA levels, PSAD is of limited additional value when compared to DRE in correctly diagnosing prostate cancer. Acute prostatitis is also a possible cause of elevated PSA. Both PSA and PSAD had no additional value in differentiating between benign prostatic hyperplasia (BPH) and histologically proven extensive prostatitis.