FREE AND TOTAL PROSTATE-SPECIFIC ANTIGEN SERUM CONCENTRATIONS DO NOT HELP TO DETECT PROSTATE-CANCER IN PATIENTS WITH URINARY OUTLET OBSTRUCTION

Objectives To determine whether different molecular forms of prostate- specific antigen (PSA) obtained before transurethral resection of the prostate (TURF) indicate the presence of prostate cancer. Patients and methods The free, total and free-to-total PSA levels were measured in 261 patients scheduled for TURF, 20 of whom had known prostate cancer . The tissue histology was compared with the PSA levels and the patien ts were followed for 5 years. Results Prostate cancer was detected in 23 of the patients (9%) who were thought to have benign disease. Norma l ranges for the distribution of the PSA levels were established based on the patients with a benign histology, but these ranges did not det ect most of the unknown cancers. The sensitivity of the total PSA test in detecting cancer was 38% and the specificity 90%. The discriminati on was no better when considering the free fraction or the free-to-tot al PSA level. However, none of the 14 patients whose cancer was missed showed general progression of the disease during the 5-year follow-up and only one died from prostate cancer. In contrast, eight of the 20 patients with a known prostatic malignancy showed general progression, and six died from the disease. Conclusion PSA testing of patients wit h outlet obstruction often failed to detect prostate cancer, but the p rognosis was moderately good in those patients in whom it was missed.