Role of PSA on Diagnosis and Clinical Stadiation of Prostatic Cancer

Abstract

The Authors review the literature and summarize the role of the PSA in early diagnosis, screening and clinical staging of prostatic carcinoma. Both advantages and limits of the test are emphasized. In spite of its limited sensitivity (57%) and low positive predictive value (49%) in early diagnosis of prostate cancer, the marker has an overall diagnostic efficiency of 64-70% and provides better detection rates of the tumor than digital rectal examination (DRE) and transrectal ultrasonography (TRUS). In screening studies, additional advantages of PSA in comparison with the other tests, are objectivity and better patient acceptance. Combination of PSA with DRE and TRUS provides the best results in early diagnosis of prostate cancer. The highest detection rates are observed with a positive DRE and high levels of PSA. The main controversies concern the group of patients with negative DRE and intermediate levels of PSA (4,1-10 ng/ml; Hybritech); in these cases other parameters, such as PSA density and/or PSA velocity, can be useful. The relationship between serie levels of the marker and age of the patients can also increase the diagnostic accuracy of the test. A screening programme in subjects at risk for prostate cancer (because of age, family history and race) may be founded on the association of PSA and DRE, using TRUS only when both PSA and DRE are positive or dubious. Lastly the Authors emphasize the importance of PSA in the clinical staging of the prostatic carcinoma, especially as predictor of bone metastases.