Effect of once-weekly oral alendronate on bone loss in men receiving androgen deprivation therapy for prostate cancer - A randomized trial

Background: Androgen deprivation therapy (ADT) in men with prostate cancer is associated with bone loss and fractures. Objective: To determine whether once-weekly oral bisphosphonate can prevent bone loss and reduce bone turnover in men receiving ADT. Design: Randomized, double-blind, placebo-controlled, partial crossover trial. First-year, preplanned analysis of a 2-group, parallel-design phase. Setting: University medical center. Patients: 112 men with nonmetastatic prostate cancer receiving ADT. Intervention: Alendronate, 70 mg once weekly, or placebo. All patients received calcium and vitamin D supplementation. Measurements: Bone mineral density of the spine and hip and markers of bone resorption and formation. Results: At baseline, 39% of men had osteoporosis and 52% had low bone mass. In men treated with alendronate, bone mineral density increased over 1 year by 3.7% (95% Cl, 2.8% to 4.6%; P < 0.001) at the spine and 1.6% (Cl, 0.4% to 2.8%; P = 0.008) at the femoral neck. Men in the placebo group had losses of 1.4% (Cl, -2.7% to - 0.03%; P = 0.045) at the spine and 0.7% (Cl, -1.5% to 0.01%; P = 0.081) at the femoral neck. At 12 months, the difference between the 2 groups was 5.1 percentage points (Cl, 3.5 to 6.7 percentage points; P < 0.001) at the spine and was 2.3 percentage points (Cl, 1.0 to 3.7 percentage points; P < 0.001) at the femoral neck. Bone turnover statistically significantly decreased with active therapy compared with placebo. The groups did not differ in adverse events. Limitations: The study was short (1 year) and was not powered to detect differences in the frequency of fractures. Conclusions: Bone loss that occurred with ADT was prevented and improved with once-weekly oral alendronate. Because most men have low bone mass or osteoporosis, physicians should assess their patients' bone density and provide preventive and therapeutic measures as appropriate.