The slope associated with nadir prostate-specific antigen is prognostically significant in men with hormone-sensitive prostate cancer after primary androgen deprivation therapy

Background Prognostic indicators based on the initial prostate-specific antigen (PSA) levels, nadir PSA, and time to PSA nadir were calculated to evaluate prognosis after primary androgen deprivation therapy (PADT), as these have been reported in very few studies. We attempted to evaluate the prognostic role of the slope associated with nadir PSA in patients treated with PADT. Methods A total of 107 patients who were treated with PADT from 2015 to 2019 were reviewed. The Kaplan-Meier method and Cox regression model were used to analyze the prognostic significance of the slope associated with nadir PSA in predicting progression-free survival (PFS) and overall survival (OS). Results After PADT, the median follow-up duration was 40.1 months; 66 patients (61.7%) had disease progression, and 33 patients (30.8%) died. In the univariate analysis, T stage, N stage, nadir PSA, time to PSA nadir, nadir PSA declining slope (nPSA-DS), nadir PSA percentage declining slope (nPSA-PDS), and nadir PSA line slope (nPSA-LS) were significant predictors for PFS and OS. The multivariate analysis showed that a higher nPSA-DS (> - 0.74) and lower PSA nadir (<= 0.16 ng/ml) were independent predictors for prolonged survival. The significance of nPSA-DS and nPSA was supported by the analysis of nPSA-DS and nPSA as time-dependent covariates. The combined analyses demonstrated that patients with a higher nPSA-DS and lower PSA nadir had the best PFS and OS. Conclusions The slope associated with the nadir PSA of nPSA-DS was a significant independent predictor for patients treated with PADT. Nadir PSA and nPSA-DS have a synergistic effect on prognosis.