Follow-up study of chemotherapy plus hormone therapy for biochemical relapse after definitive local therapy for prostate cancer.

Abstract

4657 Background: Treatment options for prostate cancer (PCa) patients with biochemical relapse (BR) after local therapy include surveillance, salvage local therapy, androgen deprivation therapy (ADT) and clinical trials. We previously reported the feasibility of chemotherapy and ADT for a cohort of 62 men with BR with a median follow-up (f/u) of 3.1 years (JCO 2006, 24:5408-13). We now report longer term f/u of this cohort. Methods: Treatment was 4 cycles of docetaxel (D) (70mg/m2) every 3 weeks and estramustine 280 mg TID (days 1-5) followed by 15 months of goserelin acetate/bicalutamide. The primary endpoint was proportion of men whose PSA < 0.1 with recovered testosterone (T) 5 years after completion of protocol therapy. Secondary endpoints included time to progression (TTP), time to re-initiate ADT, the proportion of patients with castration-resistant prostate cancer (CRPC), and overall survival (OS). Progression was defined as 2 serial rises PSA (> 2.0 ng/ml in radiation only patients and > 0.2 ng/ml in prostatectomy patients) or reinitiation of ADT for rising PSA. Results: Sixty two patients were in the original cohort. Median f/u since the start of D was 7.9 years (range: 1.3-11.1) and 43 had f/u data 5+ years after completion of protocol therapy. At 5 years after protocol therapy, 6 (10%) patients had PSA <0.1 (4 undetectable); 8 (13%) had PSA> 0.1 (0.1-0.4 in 5 and 1.6-3.7 in 3) but without reinitiation of ADT. Of the 14 men (23%), 13 have recovered T to assay normal range, and one had T level of 59 ng/dL. Median TTP after the start of D was 35.0 months (95% CI: 31.7, 39.2). At the time of analysis, 39 men (63%) restarted ADT, 20 men had CRPC, and 9 had received chemotherapy. Median time to reinitiation of ADT from completion of trial was 33.9 months (range: 0-107.6). Median OS was not yet reached and there were 15 deaths (7 PCa specific). Conclusions: Chemotherapy plus ADT resulted in durable (> 5 years) complete responses (<0.1) in 6/62 men (10%). 23% of men have not reinitiated ADT 5 years from completion of protocol ADT.