Prostatic specific antigen and prostatic acid phosphatase in the monitoring and staging of patients with prostatic cancer.

Serum prostatic specific antigen and prostatic acid phosphatase levels were measured retrospectively and evaluated in 357 men with benign prostatic hypertrophy and in 209 men with various stages of prostatic carcinoma. Although prostatic specific antigen values were elevated in 21 per cent of the patients with benign prostatic hypertrophy, the elevations usually were low and did not interfere with clinical interpretation. Prostatic specific antigen was elevated in 98 per cent of 86 men with active stage D2 disease; in 22 per cent of the men prostatic specific antigen was the only elevated marker. In contrast, prostatic acid phosphatase was the only elevated marker in 1 per cent of the patients with stage D2 disease and neither marker was elevated in 2 per cent. Among 74 patients in whom prostatic specific antigen and prostatic acid phosphatase determinations were made before radical prostatectomy, prostatic specific antigen was elevated substantially (greater than 10 ng. per ml.) in 59 per cent (26 of 44) with extracapsular disease and in only 7 per cent (2 of 30) without extracapsular disease. More importantly, of those 28 patients with substantially elevated prostatic specific antigen levels 26 (93 per cent) had extracapsular disease. Serial serum measurements showed that prostatic specific antigen either reflected or predicted clinical status in more than 97 per cent of the patients. We conclude that prostatic specific antigen is an excellent serum tumor marker for monitoring patients with prostatic carcinoma and that it surpasses prostatic acid phosphatase in this regard. Prostatic specific antigen also may be useful in staging prostatic carcinoma and it may change our attitudes significantly about the therapeutic responses to this cancer.