Clinical significance of serum prostate specific antigen in diagnosis of prostate cancer

Hong, Don Ho; Chai, Soo Eung

Abstract

Serum prostate specific antigen(PSA) as well as serum prostate acid phosphatase(PAP), the reference serum marker and digital rectal examination were measured to evaluate the clinical significance according to the diagnosis and stage of prostate cancer in 17 patients with prostate cancer & 40 patients with BPH proven pathologically, 21 normal control group free of prostate disorders from June. 1991 to June, 1992. As the mean PSA value (+/-S.D.) was 92.75 +/-16.30ng/ml for prostate cancer. 16.52 +/-2.85ng/ml for BPH and 1.51 +/-0.17 for normal control group and the mean PAP value( +/-S.D.) was 12.33 +/-3.73ng/ml, 1.48 +/-0.21ng/ml and 0.70 +/-0.1ng/ml each other, there- fore the mean PSA value in prostate cancer group revealed statistical significance(p <0.01). PSA was more sensitive and nearly same specific as PAP in diagnosis of prostate cancer(n=20ng/ml). The diagnostic accuracy of PSA was higher than PAP, positive predictive value was highest in PSA(n=20ng/ml) with abnormal digital rectal examination. The higher of the PSA, PAP value, the higher stage of prostate cancer and there was slight increase in PSA value as mush as increased grade of prostatic cancer. And serum PSA level was determined during the follow up after endocrine or combined chemotherapy and as the results 4 of 8 patients revealed normal PSA value and improvement of clinical symptoms within 2.8 months. We concluded that PSA was a simple and useful method for detection of prostate cancer and follow up after treatment, but by strict statistical criteria alone, PSA by itself didn`t qualify as an effective screening tool. Therefore if in PSA combined with digital rectal examination and transrectal ultrasonography and especially combined with PSAD and PSAV in case of 4-20ng/ml in serum PSA value it might be very useful in early diagnosis and therapeutic monitoring of prostate cancer.