Zoledronic acid combined with androgen-deprivation therapy may prolong time to castration-resistant prostate cancer in hormone-naïve metastatic prostate cancer patients – A propensity scoring approach

OBJECTIVE: To clarify the oncological benefit of zoledronic acid for hormone-naïve metastatic prostate cancer, patient outcome of androgen deprivation therapy with zoledronic acid (ADT + Z) and androgen deprivation therapy alone (ADT) was compared. METHODS: Fifty-two patients with pathologically confirmed metastatic prostate cancer were prospectively enrolled and treated with combined androgen blockade (goserelin and bicalutamide) with zoledronic acid (4 mg every 4 weeks for 24 months). A propensity score-match with logistic regression analysis was applied to select 50 pair-matched cohorts (both from ADT + Z and from historical control cohorts who had undergone ADT alone), and patient outcomes were compared. RESULTS: Patients with ADT + Z had significantly longer time to progression (TTP) than those with ADT (median TTP; 24.2 vs. 14.0 months, p = 0.0092), while no significant difference of overall survival between two groups (p = 0.1502). Multivariate analysis for biochemical recurrence revealed treatment with ADT was the sole independent prognostic factor (HR: 1.724, 95% CI: 1.06–2.86, p = 0.0297). CONCLUSION: Combination of zoledronic acid with ADT may prolong time to castration resistant prostate cancer.