[Usefulness of prostatic specific antigen (PSA) for diagnosis and staging of patients with prostate cancer].

The incorporation of prostatic specific antigen (PSA) to clinical practice revolutionized diagnosis and modified the epidemiology of prostate cancer(PCa). Although it lacks of many of the characteristics of an ideal tumor marker, it is the marker most used for diagnosis and follow up of any type of cancer. It represents the best clinical tool we currently have available for screening and staging of PCa. On the contrary, the greatest limitation PSA presents is its lack of tumor specificity. The use of PSA molecular derivatives and isoforms tries to solve, at least in part, its limitations. As a matter of fact, the use of % free PSA and PSAD significantly increases the test specificity for diagnosis and, the use of derivatives evaluating PSA temporary kinetics (PSAV and PSADT) represent very useful tools to estimate líquiprognosis during disease treatment and follow up. With the ongoing development of new markers for PCa, It is likely the role of PSA in diagnosis and staging of the disease will be modified.