Objective: The influence of prostate-specific antigen (PSA) kinetics on the outcome of metastatic prostate cancer (PCa) after androgen-deprivation therapy (ADT) remains poorly characterised. We evaluated the prognostic significance of PSA nadir and time to PSA nadir as well as their interactive effect on prostate cancer-specific mortality (PCSM) and all-cause mortality (ACM) after ADT.
Methods: A total of 650 men with advanced or metastatic PCa treated with ADT were studied. The prognostic significance of PSA nadir and time to PSA nadir on PCSM and ACM were analysed using Kaplan-Meier analysis and the Cox regression model.
Results: On multivariate analysis, clinical M1 stage, Gleason Score 8-10, PSA nadir ≥ 0.2 ng/ml and time to PSA nadir < 10 months were independent predictors of PCSM and ACM. The combined analysis showed that patient with higher PSA nadir and shorter time to PSA nadir had significantly higher risk of PCSM and ACM compared to those with lower PSA nadir and longer time to PSA nadir (hazard ratios = 6.30 and 4.79, respectively, all P < 0.001).
Conclusions: Our results suggest that higher PSA nadir level and faster time to reach PSA nadir after ADT were associated with shorter survival for PCa.