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The analysis of some factors that influence on serum PSA level in localized prostate cancer patients: mathematical model.

INTRODUCTION
Serum prostate specific antigen (PSA) concentration in localized prostate cancer (PCa) patients depends of numerous factors related to tumor, prostate and the patient. Tumor factors include tumor volume, localization, growth rate and aggressiveness. Prostate factors include prostate volume, the activity of dihydrotestosterone (DHT) and PSA synthesis. Host factors include androgenic status and total blood volume.


OBJECTIVE
to discuss all the possible factors that influence on serum PSA levels in localized PCa patients. To present the mathematical model that predicts serum PSA concentration in localized PCa patients.


METHODS
Mathematical model is based on the hypothesis that tumor-related PSA molecules are released from the epithelial prostatic cells around the tumor, so called "Destruction Zone" around the tumor (DZ). The amount of PSA is dependent of DZ volume. Moreover, DZ volume depends on tumor volume, tumor localization in the prostate and tumor growth rate.


RESULTS
The study offers the wide spectrum of PSA values, dependent on tumor, prostate and patient characteristics. These values are comparable with the empirical results in the literature, especially if tumor-volume doubling time of three years is entered into the calculations.


CONCLUSION
Although with some limitations, this mathematical model can explain the great variety of PSA serum concentrations in PCa patients.