Effects of alendronate on bone mineral density in men with prostate cancer treated with androgen deprivation therapy.

Bone mineral density (BMD) is low in men with prostate cancer treated with androgen deprivation therapy (ADT). Intravenous bisphosphonates have been shown to prevent the bone loss, however, the effectiveness of oral bisphosphonates have not been studied in this population. In this retrospective cohort study, we examine the effect of alendronate on BMD in men with prostate cancer receiving ADT. We reviewed the charts of patients receiving ADT referred from the VA Urology Clinic for BMD measurements. Forty seven patients had follow up BMD measurements (17.6+8.3 months). Twenty-two men (47%) were also receiving alendronate 70 mg every week. There was a statistically significant difference (p<0.05) in the percent change of BMD per year at the spine (-1.29+/-0.7% vs. +1.41+/-0.7%), total hip (-0.94+/-0.6% vs. +0.97+/-0.5%), femoral neck (-2.17+/-0.7% vs. +0.32+/-0.6%) and trochanter (-2.01+/-0.7% vs. +0.79+/-0.8%) in the patients not treated compared to those treated with alendronate. In the four other measured sites at the radius (proximal, mid, ultra distal and total), there were no statistically significant differences (p>0.05). These findings confirm that bone loss occurs in men receiving ADT at all sites measured. The use of alendronate prevents bone loss at the spine and hip, but does not seem to have the same protective effect at the radius.