Clinical efficacy of prostate-specific antigen testing in patients with prostate disease

Prostate-specific antigen (PSA) has become the most commonly used marker for the detection of prostatic adenocarcinoma (PCa) in recent years. To understand the clinical value of PSA testing in patients with prostate disease, the preoperative serum PSA values of 562 patients who underwent prostatic surgery from April 1993 to December 1995 were correlated with histologic findings in samples taken during surgery. Histopathologic findings revealed 93 cases of PCa and 469 cases of benign prostatic hyperplasia (BPH). Of the 220 patients with a serum PSA level within the normal range (0-4 ng/mL), PCa was diagnosed in six (2.7%) cases. However, among the 342 patients (61%) who had serum PSA > 4.0 ng/mL, BPH was diagnosed in 225 (75%) patients. With a PSA cutoff value of 4.0 ng/mL, the sensitivity, specificity and positive predictive value of PSA in distinguishing PCa from BPH were 94%, 45% and 25%, respectively. Raising the cutoff value to 10 ng/mL enhanced the specificity (76%) and positive predictive value (42%) with a slight compromise in sensitivity (85%). Of the 469 patients with BPH, 255 (54%) had a serum PSA > 4.0 ng/mL and 107 (24%) had a serum PSA > 10.0 ng/mL. Prostate volume, histologically documented prostatic inflammation and history of urinary retention prior to PSA determination may partly explain the abnormal elevation of serum PSA in patients with BPH. Our data confirmed the sensitivity of PSA in the detection of PCa in a country with a low incidence of PCa. However, a considerable proportion of patients with BPH had elevated serum PSA levels caused by factors unrelated to malignancy. Raising the cutoff value of PSA or employing adjunct parameters derived from PSA determination may be helpful in improving the diagnostic efficacy of PSA.