PROSTATE-SPECIFIC ANTIGEN AND PROSTATE ACID-PHOSPHATASE IN THE DETECTION OF EARLY PROSTATE-CANCER AND THE PREDICTION OF REGIONAL LYMPH-NODE METASTASES

Serum values of prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) were determined in 180 patients prior to pelvic lymphadenectomy and radical prostatectomy and in 40 patients prior to pelvic lymphadenectomy alone. In all tumor stages, PSA was superior to PAP in detecting cancer of the prostate. By PSA determination using a cutoff level of 4 ng/ml (Tandem(R) assay), 28.8 % of the patients with prostate cancer, stage pT2pN0M0, and 17.8 % of the cases with a stage pT3pN0M0 tumor could not be detected. All these tumors had been noticed, however, by digital rectal examination. This indicates that PSA determination cannot replace digital rectal examination as a screening method for prostate cancer. In this study, it was possible neither by PSA nor by PAP to define a practicable cutoff level for patients with and without lymph node metastases. A clear differentiation between the stages pT2pN0M0 and pT3PN0M0 was not possible by either PSA or PAP alone.