Long-term follow-up of a phase II trial of chemotherapy plus hormone therapy for biochemical relapse after definitive local therapy for prostate cancer

Abstract

Objective: To evaluate long-term follow-up of a phase II trial of chemohormonal therapy in 62 men with prostate cancer biochemical relapse (BR).

Methods: Treatment was 4 cycles of docetaxel (70 mg/m(2)) every 3 weeks and estramustine 280 mg three times a day (days 1-5) followed by 15 months of goserelin acetate/bicalutamide. The primary endpoint was the proportion with prostate-specific antigen (PSA) <0.1 with recovered testosterone 5 years after completion of therapy. Secondary endpoints included time to progression (TTP), time to reinitiate androgen deprivation therapy (ADT), the proportion with castration-resistant prostate cancer (CRPC), and overall survival (OS).

Results: Median follow-up was 8.6 years (range 1.3-11.1 years). At 5 year follow-up, 7 patients (11%) had PSA <0.1 (5 undetectable); 8 (13%) had PSA >0.1 but without reinitiation of ADT (median PSA 0.37). Of the 15 (24%) men without reinitiation of ADT, and 14 have recovered testosterone to normal range. Median TTP for the complete cohort was 35.0 months (95% confidence interval [CI] 31.7-39.2). Baseline PSA <3.0 ng/dL, no prior ADT, and prostatectomy (vs radiation) were associated with longer TTP (P = .0001, P = .0055, and P = .0398, respectively). At the time of analysis, 42 men (68%) had restarted ADT, 23 men had CRPC (37%), and 11 (18%) had chemotherapy. Median time to reinitiation of ADT was 32.6 months (range 0-107.6 months). Median OS has not been reached; there were 15 deaths.

Conclusion: Chemotherapy plus ADT for BR resulted in durable (>5 years) complete responses (<0.1 ng/mL) in 7 men (11%). Twenty-four percent of men have not re-initiated ADT 5 years from completion of protocol therapy.