Biochemical control of the combination of cyclooxygenase-2 inhibitor and I-brachytherapy for prostate cancer: Post hoc analysis of an open-label controlled randomized trial.

Objectives: To evaluate the use of cyclooxygenase-2 inhibitors in patients receiving low-dose-rate brachytherapy for prostate cancer.

Methods: A total of 310 patients with prostate cancer (cT1c-3aN0M0) who received low-dose-rate brachytherapy between May 2010 and July 2013 were enrolled and allocated to one of the two treatment groups (tamsulosin alone 0.2 mg/day for 6 months vs tamsulosin 0.2 mg/day for 6 months plus celecoxib 200 mg/day for 3 months). The primary end-point was the chronological change in international prostate symptom score, and the number of patients was assessed for the primary end-point. Biochemical recurrence-free, cancer-specific survival and overall survival rates 5 years after the last patient received low-dose-rate brachytherapy were retrospectively examined.

Results: The median follow-up period after low-dose-rate brachytherapy was 72.0 months (range 3-99 months). A total of 12 (3.9%) patients experienced biochemical recurrence. The biochemical recurrence-free rate in the celecoxib group (5-year biochemical recurrence-free rate 98.5%) was significantly better (log-rank test P = 0.023, 95% confidence interval 0.07-0.63, hazard ratio 0.20) than that in the tamsulosin group (5-year biochemical recurrence-free rate 93.4%). None of the patients died from prostate cancer. However, 14 (4.5%) patients died of other causes. No significant difference was observed in terms of overall survival between the celecoxib and tamsulosin groups.

Conclusions: The combination of cyclooxygenase-2 inhibitor and low-dose-rate brachytherapy can contribute to a better biochemical control of prostate cancer.