Prostate-specific antigen in prostatic carcinoma.
To evaluate the clinical and prognostic value of prostate-specific antigen (PSA) for the detection of tumor and tumor growth after therapy, 520 sera from 246 patients with prostatic carcinoma, 990 sera from patients with BPH, and 1,488 sera from patients with other urological diseases were analyzed. The values ranged from 0.1 to 1,828.9 ng/ml. 51% of all values were about 2.5 ng/ml, and 76.8% of all values about 10 ng/ml. The commercial recommendation for the cutoff values is 2.5 ng/ml (IBL, FRG). In patients with benign prostatic hypertrophy this cutoff means 61% false-positive results, which makes the test highly sensitive but unspecific. In prostatic carcinoma patients this borderline means a false-negative result in 9.75% (24 of 246). By determining the cutoff at 10 ng/ml in our series, a false-negative result appeared in 14.6%. Therefore a plea is made for the 10-ng/ml cutoff. In follow-up studies a marked decline in PSA values after transurethral resection or antiandrogen therapy (orchiectomy/Zoladex/ICI/flutamide, Essex). Generally, the greater the PSA levels the more advanced the stage of disease. These data suggest that PSA may be a useful adjuvant marker for monitoring tumor growth in patients with regionally confined tumor.