The study covered 44 patients with localized and locally advanced prostate cancer (PC), who were followed up for at least 18 months after brachytherapy. A significant reduction in the level of prostatic specific antigen (PSA) in the blood of patients was observed 3 months after brachytherapy and tended to decrease further during a 12-month follow-up. It is the time after brachytherapy that may be considered as a criterion for a primary tumor response to the therapy. There were individual differences in the velocity and decrease rate of PSA levels during the therapy: in 30 (68.2%) patients, PSA values were in the range of 0.01—0.98 ng/ml (mean 0.39±0.31 ng/ml) while in 14 (31.8%) patients, those were 1.10—6.20 ng/ml (3.02±1.79 ng/ml). A certain correlation was found between the parameters of PSA (baseline PSA level, time course of changes, and kinetics of PSA levels) and the outcome of the disease. A more objective evaluation of the efficiency may be made after increasing the time of a follow-up and the number of patients after brachytherapy
