The impact of bicalutamide (Casodex) monotherapy on bone mineral density (BMD) was investigated in patients with locally advanced prostate cancer. BMD was assessed after treatment with bicalutamide 150 mg daily ( n=21) or by medical castration (goserelin acetate 3.6 mg every 28 days) ( n=8) for a median of 287 weeks. In 38% of castration compared with 17% of bicalutamide patients, femoral neck Z-scores were < or =-1 SD of the reference value (accepted as a two to three times increased risk of fracture) and T-scores were < or =-2.5 SD (World Health Organization definition of osteoporosis in white females). Total hip Z-scores were < or =-1 in 43% of castration patients and 13% of bicalutamide patients. In 38% of patients, lumbar spine BMD was affected by degenerative disease. These preliminary data suggest that there may be an advantage in terms of BMD in using bicalutamide monotherapy compared with castration; a benefit confirmed in a recent prospective randomised study.