PROSTATE-SPECIFIC ANTIGEN IN THE DIAGNOSI S OF ORGAN CONFINED CURABLEPROSTATE-CANCER

Prostate cancer is now the most common cancer and the second most comm on cause or: death from cancer among men. Several studies have shown a frequency of autopsy-detected cancer of 40% in men over 50 years of a ge. Tn contrast, the lifetime probability of prostate cancer being dia gnosed clinically is only 8%. Thus histologically documented prostate cancer only becomes clinically relevant if the tumors are >0.5 cm(3) a nd the life expectancy exceeds 10 years. Therapy with curative intenti on is only possible for organ confined disease. Because disease specif ic survival is about 80-90%, after 10 years for conservative treatment of organ confined disease, early detection of prostate cancer is usef ul For patients with a life expectancy >10 years. Organ confined prost ate cancer is usually asymptomatic. The use of prostate specific antig en (PSA) combined with digital rectal examination (DRE) results in a 2 -3 fold increase in prostatic carcinoma detection rate, especially of organ confined disease, by PSA. In men with a minimally elevated PSA v alue of 4-10 ng/ml (Hybritech Assays), 25% will have a prostatic carci noma regardless of the finding of the DRE, which would have reached cl inical significance in the follow-up. The indication for biopsy should be established at an early date. There is no support for the common o pinion that early detection programs detect clinically unimportant can cers. 95% of tumor volumes are >0.5 cm(3). Furthermore only 3-5% of su bjects show prostate cancer in detection programs though 8% will devel op clinical symptoms of prostate cancer during their lifetime. This di fference is a reason for longitudinal programs with PSA and DRE contro l once a year, as proposed by the American Cancer Society and the Amer ican and Canadian Urological Association, in contrast to other health care organizations, which would wait with general screening until data from prospective randomized trials with beneficial effects of screeni ng are available. To introduce prostate cancer therapy with curative i ntention for symptomatic patients as well, the cancer should be detect ed below a PSA level of 10 ng/ml. Insufficient specificity of PSA (2-4 patients have to undergo biopsies to detect one cancer patient) is st ill an unsolved problem.