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The clinical significance of prostate specific antigen and its free fraction for detection of prostate cancer.
BURSÍKOVÁ, Michaela
Currently, the determination of prostate-specific antigen (PSA) and free prostate-specific antigen (fPSA) has been used for a targeted detection of early stages of prostate cancer; together with other parameters this method enables the monitoring of the course of the already diagnosed disease and the treatment effect. The goal of the Bachelor's Thesis is to execute the literature search concerning prostate cancer and benign prostatic hyperplasia and to describe methods for determination of PSA and fPSA. In addition, to process the measured data and to assess in which age group the number of requests for PSA testing is highest and whether the patients with a higher value of PSA (based on the age specification) undergo any other laboratory tests. The measured data are further processed in terms of three formulated hypotheses. The theoretical part of the thesis deals with findings concerning the anatomical structure and physiological functions of prostatic tissue in a human organism. In this part, diseases, which may affect prostate, are described. The focus is on diseases, which may cause the elevation of laboratory-determined prostate-specific antigen and its free fraction. These diseases include prostatitides, benign prostatic hyperplasia and prostate cancer. In addition, the etiology of the disease, its clinical symptoms, stages and the diagnostic procedure in the patients coming with a suspicion of prostate cancer are described. The theoretical part also contains the laboratory method used to determine prostate-specific antigen, free prostate-specific antigen and conditions which might affect pre-analytical and analytical phases of their testing. Furthermore, some new biochemical parameters, which may supplement or replace the existing laboratory markers of prostate cancer in the future are provided. However, these new methods must be tested in additional studies. The aforementioned part is followed by a description of the analytical systems available for the laboratory measurement of prostate-specific antigen and free prostate- specific antigen. The principle of the measurement and the procedure of the analysis as such are explained as well. In the conclusion of the theoretical part, I provide an outline of the possibilities to monitor trends in PSA laboratory values in patients who were diagnosed with prostate cancer based on their bioptic samples histology. For the monitoring of an increase in PSA values, the monitoring of PSA velocity (PSAV) and doubling time (time necessary for PSA increase to double) are used. These methods are not to diagnose prostate cancer; they are important from the prognostic point of view only. The practical part was executed in Klinické laboratoře Tábor, a.s. The measurements were performed over a period of three years (2011 - 2013) and an extensive data set, which includes 11 357 PSA tests and 2 074 fPSA tests, was collected. The results are depicted in the respective diagrams and tables. All the measured values were divided into six groups depending on the age of the tested patients. In group one of patients younger than 39 years, 243 PSA and 13 fPSA were measured. In the remaining age groups, the number of tests increased gradually up to the age of 69 years; in the seventh and eighths decades of age the number of tests gradually decreased. The number of tests executed in individual groups was as follows: 40 to 49 years 1 305 PSA and 93 fPSA, 50 to 59 years 3 462 PSA and 519 fPSA, 60 to 69 years 3 852 PSA and 785 fPSA, 70 to 79 years 1 941 PSA and 495 fPSA, above 80 years 554 PSA and 162 fPSA. Dates of PSA tests were divided in each group depending on the cut-off values, into below cut-off PSA (values corresponding with the standard) and above cut-off PSA (values exceeding the limits of the standard). The cut-off value is different for each age group and increases with increasing age.
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