PSA Nadir and Time to PSA Nadir Following Androgen Deprivation Therapy are the Predictors for Castration-Resistant Prostate Cancer in Patients with Metastatic Prostate Cancer

Purpose: To evaluate the influence of nadir prostate-specific antigen (PSA) level and time to PSA nadir following androgen deprivation therapy (ADT)on disease progression of castration-resistant prostate cancer (CRPC) in patients with metastatic, hormone-sensitive prostate cancer (mHSPC). Patients and methods: A total of 90 patients with metastatic, hormone-sensitive prostate cancer treated with androgen deprivation therapy in our hospital were included in our retrospective study. Patients’ characteristics, PSA at PADT initiation (initial PSA), PSA nadir, TTN, follow up time, CRPC event were analyzed using Kaplan-Meier analysis and Cox regression model. Results: At a median follow-up of 12 months, 57 patients (63.3%) showed disease progression of CRPC Both PSA nadir and time to PSA nadir (TTN) was independent and significant predictors of CRPC event. Patients with higher PSA nadir (≥0.2ng/dL) and shorter time to PSA nadir (TTN <6 months) had significant shorter time to CRPC. Meanwhile, the Gleason score, age and initial PSA werenot significant predictors of disease progression. In the combined analyses showed patients with higher of PSA nadir and shorter TTN had significantly higher risk for CRPC event compared to lower PSA nadir and longer TTN (HR 69.243, p-value< 0.001) Conclusion: We concluded that both higher PSA nadir and shorter time to PSA nadir are significant predictors of CRPC in patients with metastatic, hormone-sensitive prostate cancer receiving ADT.