Preventive effect of risedronate on bone loss in men receiving androgen‐deprivation therapy for prostate cancer

Aim:  Androgen-deprivation therapy for prostate cancer decreases bone mineral density and increases the risk of fracture. The effect of risedronate, a potent third-generation oral bisphosphonate, on bone loss during androgen deprivation therapy was investigated. Methods:  Sixty-one prostate cancer patients with a mean age (±SD) of 79 ± 6 years who had received androgen deprivation therapy for 42 ± 29 months were enrolled, and were treated with 2.5 mg of risedronate daily for six months. Bone mineral density was measured at the femoral neck, lumbar spine, and ultradistal radius by dual energy X-ray absorptiometry. The percent change of bone mineral density after treatment with risedronate was calculated as the primary efficacy variable. Urinary N-telopeptide of type I collagen was measured as a bone resorption marker. Results:  Bone mineral density remained stable in the femoral neck and radius during risedronate therapy. In contrast, the bone mineral density of the lumbar spine showed a significant increase from 1069 ± 488 mg/cm2−1112 ± 497 mg/cm2 (P < 0.001), representing a gain of 4.9 ± 8.9%. Urinary N-telopeptide of type I collagen decreased significantly (P < 0.001) after three months of risedronate treatment. Conclusions:  Risedronate could prevent and reverse bone loss in men receiving androgen deprivation therapy for prostate cancer by inhibiting bone resorption.