Survival outcomes of Chinese metastatic prostate cancer patients following primary androgen deprivation therapy in relation to prostate-specific antigen nadir level

Aim: To evaluate the progression-free survival (PFS), cancer-specific survival (CSS) and overall survival (OS) of Chinese metastatic prostate cancer patients following primary androgen deprivation therapy (ADT) in relation to prostate-specific antigen (PSA) nadir level. Methods: All Chinese prostate cancer patients with bone metastases who were treated with primary ADT from 2000 to 2009 were included. Patients' and disease characteristics were recorded. Patients were categorized into two PSA nadir groups (<= 1.0 and >1.0 ng/mL). Associations of PSA nadir with PFS, CSS and OS were analyzed with Kaplan-Meier and Cox regression analyses. The survival outcomes of the two PSA nadir groups were presented. Results: Four hundred nineteen patients were included in the study. PSA nadir appeared to be a good predictor for PFS (hazard ratio [HR] 1.86, 95% confidence interval [CI] 1.35-2.56, P < 0.001), CSS (HR 1.60, 95% CI 0.98-2.64, P = 0.063) and OS (HR 1.77, 95% CI 1.20-2.41, P < 0.001) upon multivariate Cox regression analyses. In the PSA nadir groups of <= 1.0 and >1.0 ng/mL, the median PFS were 15 and 10 months, and the 1-year PFS rates were 64% and 40%, respectively; the median CSS were 42 and 27 months, and the 5-year OS rates were 53% and 28%, respectively; and the median OS were 41 and 24 months, and the 5-year OS rates were 45% and 19%, respectively. Conclusions: Higher PSA nadir was associated with shorter PFS, CSS and OS in Chinese metastatic prostate cancer patients following primary ADT. The survival outcomes may serve as references in deciding the best treatment strategy in Chinese prostate cancer patients.