What is the possible role of PSA doubling time (PSADT) and PSA velocity (PSAV) in the decision-making process to initiate salvage radiotherapy following radical prostatectomy in patients with prostate cancer?

This article is an attempt to present a contemporary view on the role of the kinetics of PSA levels as defined by PSA doubling time (PSADT) and PSA velocity (PSAV) in the decision-making process to initiate salvage radiotherapy in patients with prostate cancer after radical prostatectomy (RP). The dynamics of the rise of PSA levels may be an early endpoint parameter, preceding the diagnosis of distant metastasis or death due to prostate cancer based on a single PSA determination. Thus, it seems reasonable to include the kinetics of PSA levels, apart from single PSA determination, in the decision-making algorithm. In a group of patients after RP, PSADT might be an early endpoint that could replace cause-specific survival rate as a late endpoint. PSADT allows distinguishing subgroups of patients at high risk of distant metastases and death, which in turn may lead to a change in the further treatment strategy. Therefore, patients with short PSA doubling time should become a subgroup, in which hormonal therapy should be considered. To date, there is no unanimous consent to accept the criteria of assessment of the dynamics of PSA levels as determinants of treatment in case of recurrences following RP. However, a number of non-randomized clinical trials in patients after RP suggest it would be useful to include these parameters in the decision-making process. For instance, a relationship was found between increased PSA velocity (>2 ng/mL/year) before initiation of oncological treatment and increased (12-fold) risk of death. A number of well-documented retrospective analyses show that PSADT is one of the most important parameters to describe the disease aggressiveness. It has to be stressed that single determination of PSA levels is much less precise in terms of describing the biological aggressiveness of prostate cancer than PSADT. Of course, the question regarding the need to include the PSA levels kinetic parameters as crucial elements of patient management algorithms can be answered in a definitive manner only by randomized clinical trials.