Comparative study of the protective effect of different intravenous bisphosphonates on the decrease in bone mineral density in patients submitted to radical prostatectomy undergoing androgen deprivation therapy. A prospective open-label controlled study

OBJECTIVES: To establish whether androgen deprivation therapy (ADT) promotes osteoporosis and osteopenia METHODS: Ninety-four prostatectomized men with rising prostrate-specific antigen (PSA) were enrolled into the placebo group (31), monthly i.v. clodronate (39) or monthly i.v. zoledronic acid (24) groups for 36 months. Dual-energy X-ray absorptiometry measured the bone density in the lumbar (L2-L4) area. chi(2) and anova tests were used to analyze data.. RESULTS: After 6 months of androgen deprivation, 17 of the 31 control cases developed osteopenia in the lumbar area. At 12 months, nine control cases had osteoporosis with 13 additional cases of osteopenia. At the end of the 36-month study period, the untreated group showed an average bone mineral density (BMD) loss of -1.82 (+/-0.94) with 13 cases of osteopenia and 18 cases of osteoporosis. The clodronate group had two cases of osteoporosis out of 39 subjects after 6 months of ADT with 28 developing osteopenia and seven cases of osteoporosis after 36 months of follow up. Mean BMD loss in this group was -0.72 (+/-0.34). The zoledronic acid studied arm had seven cases of osteopenia after 6 months of ADT while 20 and five cases developed osteopenia and osteoporosis, respectively, after 36 months of follow up. The former group had a mean bone loss of -0.88 (+/-0.32). There was statistical difference for BMD loss in the treated groups starting at 6 months in comparison to the control group. CONCLUSIONS: Six months of ADT promoted impressive bone loss in the lumbar area of the non-treated patients. This tendency is progressive and may be delayed by i.v. bisphosphonates.