Effect of Once-Weekly Oral Alendronate on Bone Loss in Men Receiving Androgen Deprivation Therapy for Prostate Cancer

Abstract

Androgen deprivation therapy (ADT) in men with prostate cancer is associated with bone loss and fractures. To determine whether once-weekly oral bisphosphonate can prevent bone loss and reduce bone turnover in men receiving ADT. Randomized, double-blind, placebo-controlled, partial crossover trial. First-year, preplanned analysis of a 2-group, parallel-design phase. University medical center. 112 men with nonmetastatic prostate cancer receiving ADT. Alendronate, 70 mg once weekly, or placebo. All patients received calcium and vitamin D supplementation. Bone mineral density of the spine and hip and markers of bone resorption and formation. 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% CI, 2.8% to 4.6%; P < 0.001) at the spine and 1.6% (CI, 0.4% to 2.8%; P = 0.008) at the femoral neck. Men in the placebo group had losses of 1.4% (CI, -2.7% to - 0.03%; P = 0.045) at the spine and 0.7% (CI, -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 (CI, 3.5 to 6.7 percentage points; P < 0.001) at the spine and was 2.3 percentage points (CI, 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. The study was short (1 year) and was not powered to detect differences in the frequency of fractures. 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. ClinicalTrials.gov registration number: NCT00048841.