Optimal PSA threshold for androgen-deprivation therapy in patients with prostate cancer following radical prostatectomy and adjuvant radiation therapy

Purpose: The benefits of early administration of androgen-deprivation therapy (ADT) in patients with prostate-specific antigen (PSA)-only recurrent prostate cancer (PCa) following radical prostatectomy (RP) are controversial. We investigated the impact of early versus delayed ADT on survival outcomes in patients with non-metastatic, localized or locally advanced PCa who received radiation therapy (RT) following RP and later developed distant metastasis. Materials and Methods: A retrospective analysis was performed on 69 patients with non-metastatic, localized or locally advanced PCa who received RT following RP and later developed distant metastasis between January 2006 and December 2012. Patients were stratified according to the level of PSA at which ADT was administered (<2 ng/mL vs. ≥2 ng/mL). Study endpoints were progression to castration-resistant prostate cancer (CRPC)-free survival and cancer-specific survival (CSS). Results: Patients were stratified according to the criteria of 2 ng/mL of PSA at which ADT was administered, based on the Youden sensitivity analysis. Delayed ADT at PSA ≥2 ng/mL was an independent prognosticator of cancer-specific mortality (p=0.047), and a marginally significant prognosticator of progression to CRPC (p=0.051). During the median follow-up of 81.0 (interquartile range 54.2–115.7) months, patients who received early ADT at PSA <2 ng/mL had significantly higher CSS rates compared to patients who received delayed ADT at PSA ≥2 ng/mL (p=0.002). Progression to CRPC-free survival was comparable between the two groups (p=0.331). Conclusion: Early ADT at the PSA level of less than 2 ng/mL confers CSS benefits in patients with localized or locally advanced PCa who were previously treated with RP.