Phase II randomized study of radiotherapy and three-year androgen deprivation with or without concurrent weekly docetaxel in high-risk localized prostate cancer patients.

BACKGROUND: Docetaxel improves survival in patients with metastatic prostate cancer (PC). This randomized phase II trial aimed to assess the activity of weekly docetaxel with radiotherapy (RT) plus androgen deprivation in patients with high-risk localized PC, examining the benefit of nine weekly docetaxel administrations to RT plus 3 years of LHRH analogues.

PATIENTS AND METHODS: A total of 132 patients were accrued. Patients characteristics included T3-T4 (81.1%), Gleason score (GS) ≥ 8 (77.3%), PSA > 20 ng/mL (28.9%) and pN+ (18.2%). All patients included in the trial received either the standard of care control arm with LHRH analogues plus RT (Arm A) or the experimental arm (RT+weekly docetaxel -9 weekly cycles- plus 3 years of ADT, Arm B). Primary objective was percentage of patients free of biochemical recurrence within five years of randomization. Secondary endpoints included biochemical recurrence-free survival, progression free survival (PFS), overall survival (OS), clinical response rate, biochemical response rate and toxicity.

RESULTS: There was no difference between arms in terms of biochemical recurrence (93.4% at 60 months for arm A vs 85.3% for arm B (p=0.3297)). PFS at 60 months was 93.4 and 83.7% in arms A and B, respectively (p=0.2532). Five-year survival was 93.3% (95% CI 83.1, 97.45) arm A versus 93.6% (83.8, 97.55) arm B; median PFS and OS have not been reached. PSA value ≤0.2 ng/ml at 3 months after end of treatment was seen in 81.25% patients in arm A compared to 90.48% patients in arm B (p=0.2028). Biochemical recurrence-free survival was not significantly different between treatment arms. Diarrhea was the main non-hematologic toxicity. Long term follow-up has not been yet enough to meet median PFS and OS.

CONCLUSION: Concurrent weekly docetaxel can be administered safely with standard doses of radiotherapy without a significant increase in the toxicity profile. No statistically significant differences for 5-year biochemical RFS, PFS and OS has been observed when docetaxel was added to conventional treatment.