Bone mineral density changes in patients with prostate cancer during the first 2 years of androgen suppression.

PURPOSE: We characterized bone mineral density changes in patients with prostate cancer on androgen deprivation therapy during the first 2 years of uninterrupted therapy, and identified which location most reflects bone mass loss.
MATERIALS AND METHODS: Using dual energy x-ray absorptiometry, bone mineral density was prospectively assessed in patients with nonmetastatic prostate cancer at the lumbar spine and femoral neck, Ward's triangle, trochanter and total hip. Measurements were performed at baseline and yearly thereafter in patients on ADT, and at baseline and 1 year in controls (age matched patients with prostate cancer, free of biochemical progression after radical prostatectomy).
RESULTS: A total of 62 patients were included in the study, 31 in each group. Median age (70 and 69 years, respectively), mean Gleason score and mean baseline serum testosterone did not significantly differ. Patients receiving ADT experienced a significant bone mass loss at 12 months in all locations, ranging from 2.29% to 5.55% (p <0.001). In contrast, bone mineral density did not change significantly (0.64% to 1.68%) in patients not receiving ADT. In the 20 patients on ADT after 24 months, the second year decrease was not as severe, nor was it significant compared to first year values. The major bone mass loss occurred in Ward's triangle, with decreases of 5.55% at 12 months and 7.05% at 24 months.
CONCLUSIONS: Bone mineral density decreases during the first 24 months of androgen suppression with the most relevant effect occurring in the first year. Ward's triangle is the axial skeletal site that reflects the major bone mass loss. Because the deleterious impact of long-term androgen suppression on bone mineral density is inversely related to fracture risk and indirectly related to survival in patients with prostate cancer, early diagnosis and prevention of bone mass loss are warranted in these patients.