Tumour markers in prostatic carcinoma. A comparison of prostate-specific antigen with acid phosphatase.

A study was performed on 130 men to compare the level of serum prostate-specific antigen (PSA) in controls, patients with benign prostatic hyperplasia (BPH) and patients with prostatic carcinoma. The results showed that all 30 normal controls below 40 years of age had values less than 10 ng/ml. Of the 40 patients with BPH, all aged over 40 years, 13 (32.5%) had raised levels above 10 ng/ml. In the 60 patients with prostatic carcinoma, all over 40 years, 24 had localised disease (MO) and 36 had metastatic spread (M1), as judged by isotope bone scan. In patients with MO disease, 16 (66.6%) had raised PSA levels compared with 34 (94.5%) of those with M1 disease. The corresponding figures for raised prostatic acid phosphatase (PAP) values were 4% in the MO group and 52.7% in the M1 group. PSA levels reflected neither the histological grade nor the local stage of the tumour and were of no value in estimating tumour burden. PSA was found to be a valuable index in the management of prostatic cancer because of this sensitivity. Stable disease not requiring hormonal manipulation was reflected by unchanging levels of PSA, whereas progressive disease requiring hormonal therapy was reflected by an alteration in the PSA levels corresponding to the patients' response. The same group of progressive disease patients showed only a 50% rise in serum PAP levels, confirming the greater sensitivity of PSA as a measure of prostate cancer. PSA measurements should be included in any further trials on prostatic carcinoma and should be regarded as a standard marker for evaluating response to therapy.