Evaluation of prostate-specific antigen as a marker for adenocarcinoma of the prostate

Serum prostate-specific antigen (PSA) concentrations were measured in samples from 437 subjects, including patients with prostate cancer, patients with benign prostate hyperplasia (BPH), and patients with genitourinary cancer or benign genitourinary diseases other than prostatic, as well as patients who had undergone prostatectomy and healthy controls. PSA concentration was elevated (less than 10 ng/ml) in 84.4% of the patients with prostate cancer, in 14.1% of the patients with BPH, and in 10% of the patients with genitourinary cancer (as compared with 2% of the patients with benign genitourinary diseases). PSA concentration was not elevated in any of the patients who had undergone prostatectomy nor in the controls. In the same samples, the level of prostatic acid phosphatase (PAP) was increased (greater than 4 IU/L) in only 55.6% of the patients with prostate cancer and in 7.4% of the patients with BPH. According to these findings, the sensitivity of the test is 84.4% (55.6% for PAP) and the specificity is 92.9% (94.9% for PAP). The increase in PSA concentration in BPH correlates well with the prostate mass (gamma = 0.794), although there was no patient with a prostate weight higher than 30 gm and a PSA concentration lower than 5 ng/ml, and all patients with PSA concentrations lower than 4 ng/ml had prostate weight of less than 10 gm.