Purpose: Gonadotropin-releasing hormone agonists decrease bone mineral density, lean mass, and muscle size and increase fat mass in men with prostate cancer. Less is known about the effects of bicalutamide monotherapy on bone mineral density and body composition.
Patients and methods: In a 12-month, open-label study, we randomly assigned 52 men with prostate cancer and no bone metastases to receive either leuprolide or bicalutamide (150 mg by mouth daily). Bone mineral density and body composition were measured by dual energy x-ray absorptiometry and quantitative computed tomography.
Results: Mean (+/- standard error) bone mineral density of the posterior-anterior lumbar spine decreased by 2.5% +/- 0.5% in the leuprolide group and increased by 2.5 +/- 0.5 in the bicalutamide group from baseline to 12 months (P <.001). Mean changes in bone mineral density of the total body, total hip, femoral neck, and trabecular bone of the lumbar spine also differed significantly between groups (P < or =.003 for each comparison). Fat mass increased by 11.1% +/- 1.3% in the leuprolide group and by 6.4% +/- 1.1% in the bicalutamide group (P =.01). Changes in lean mass, muscle size, and muscle strength were similar between the groups. Breast tenderness and enlargement were more common in the bicalutamide group than in the leuprolide group. Fatigue, loss of sexual interest, and vasomotor flushing were less common in the bicalutamide group than in the leuprolide group.
Conclusion: In men with prostate cancer, bicalutamide monotherapy increases bone mineral density, lessens fat accumulation, and has fewer bothersome side effects than treatment with a gonadotropin-releasing hormone agonist.