Use of pretreatment prostate specific antigen doubling time to predict outcome after radical prostatectomy

Prostate-specific antigen kinetics in clinical decision-making during active surveillance for early prostate cancer--a review

CONTEXT

The kinetics of prostate specific antigen (PSA) are generally assumed to be indicative of tumour progression and are therefore used in clinical decision-making in men on active surveillance for early prostate cancer.

OBJECTIVE

This review aims to provide support for exploiting PSA kinetics in an active surveillance setting.

EVIDENCE ACQUISITION

We searched the Medline database and reviewed the evidence on both the relation between PSA kinetics before radical treatment for prostate cancer and outcome, as well as the role of PSA kinetics during active surveillance. Furthermore, the benefits and setbacks of different derivatives of PSA kinetics, minimum required time interval and number of measurements, practical recommendations, and pitfalls of their use in clinical practice are discussed.

EVIDENCE SYNTHESIS

The evidence concerning the prognostic value of the PSA velocity (PSA-V) and PSA doubling time (PSA-DT) is sparse, especially in active surveillance. PSA kinetics should therefore be combined with other diagnostic measures as the trigger for deferred radical treatment or repeat prostate biopsies. There seems to be consensus among several reports on the unfavourable outcome relating to a PSA-DT <3-4 yr and on the favourable prognostic value of a PSA-DT >10 yr or a decreasing PSA level. Online tools provide help with calculations and insight on disease development. The best method of calculation, number of measurements, and time interval between measurements is unknown for now.

CONCLUSIONS

Despite the current deficits in our understanding of the natural behaviour of early prostate cancer and its relation to serum PSA levels, and despite several secondary factors playing a role in PSA kinetics, PSA kinetics are a practical parameter we can offer men on active surveillance to assess the status of their disease.

Prostate specific antigen doubling time calculation: not as easy as 1, 2, 4

PURPOSE

Although prostate specific antigen doubling time is widely used to predict outcomes such as time to progression and prostate cancer specific mortality, clinicians may be unaware of the impact of method on prostate specific antigen doubling time calculation. We present a critical review of the literature to assess the diversity of methods used to calculate prostate specific antigen doubling time. We then describe the need for methodological consistency with the literature by showing examples from our clinical experience at our institution.

MATERIALS AND METHODS

A comprehensive review of articles evaluating prostate specific antigen doubling time as a prognostic and predictive indicator in various prostate cancer disease states was performed using PubMed. Case examples were drawn from the prostate cancer database at our institution. The database is a registry of 4,651 patients with prostate cancer who have been seen at our institution since 1998.

RESULTS

The methodology of prostate specific antigen doubling time calculation is inconsistent in the literature. Based on our experience and data presented in the literature the different methods in the literature are not always interchangeable. Small deviations from the methods outlined in a study can sometimes lead to wide variation in calculated prostate specific antigen doubling time. This variation of up to several months or longer is large enough to cause errors in assessment of prognosis and can even lead to incorrect management. The rules for prostate specific antigen doubling time calculation found in the literature can be categorized into 4 parameter groups, including method, calculation interval, data acquisition rules and data analysis rules. Case examples illustrate the importance of adherence to the literature with regard to each parameter.

CONCLUSIONS

Consistency with the literature in methodological elements of prostate specific antigen doubling time calculation is essential for the accurate calculation of prostate specific antigen doubling time. Clinicians and researchers should understand how methodological differences influence the value of calculated prostate specific antigen doubling time for purposes of patient care and research.