Intermediate PSA half-life after neoadjuvant hormone therapy predicts reduced risk of castration-resistant prostate cancer development after radical prostatectomy.

Background: The magnitude and rapidity of the tumor response to androgen deprivation is known to predict the durability of the therapy. We have investigated the predictive value of categorizing patients by the half-life of PSA under neoadjuvant androgen deprivation therapy in patients with biochemical recurrence after radical prostatectomy.

Methods: Medical records of 317 patients who received neoadjuvant androgen deprivation therapy before radical prostatectomy and developed biochemical recurrence were analyzed. The patients were categorized into five groups according to PSA half-life. Risk of developing castration resistance was evaluated by Kaplan-Meier analysis and by Cox proportional risk regression analysis.

Results: The median follow-up duration was 50.1 months (IQR 31.8-68.7) and median PSA half-life was 22.1 days (IQR 12.7-38.4). Comparison of survival curves revealed that patients in the intermediate response group showed significantly lower 5-year castration-resistant prostate cancer rate (37.5%) compared to non-response and ultra-rapid response groups (63.6%, p = 0.007; 56.1%, p = 0.031; respectively). In the multivariate regression model, intermediate response compared to non-response was associated with significantly reduced risk of castration resistance development (hazard ratio 0.397, 95% confidence interval 0.191-0.823, p = 0.013) and overall mortality (hazard ratio 0.138, 95% confidence interval 0.033-0.584, p = 0.007). When subcategorized by Gleason score, Kaplan-Meier curve revealed that, in the high Gleason score stratum, 5-year castration-resistant prostate cancer rate for intermediate response group (44.0%) was exceptionally lower than that in non-response group (66.7%, p = 0.047), while castration resistance increased in other groups.

Conclusion: Short PSA half-life as well as no response after androgen deprivation is associated with increased risk of treatment failure compared to intermediate PSA half-life.