medwireNews: Weekly administration of oral biphosphonate alendronate could reduce loss of bone mineral density (BMD) in prostate cancer patients who start androgen-deprivation therapy (ADT), show study findings.
The 1-year trial, which was conducted across 30 urology sites in Canada, showed that the regimen not only prevented bone loss and increased bone mass, but it also decreased bone turnover.
Men initiating ADT are at risk for loss of BMD and osteoporotic fractures, yet the majority of men do not receive any treatment for this side effect, explain Laurence Klotz (Sunnybrook Health Sciences Centre, Toronto, Canada) and team. Calcium and vitamin D supplementation are recommended, although there is little support for this therapy in the setting of ADT.
The team conducted an intention-to-treat analysis of 167 patients initiating ADT therapy (leuprolide acetate 30 mg intramuscularly every 4 months), who were randomly allocated to receive either once-weekly oral alendronate 70 mg or placebo. All patients also took calcium 1 g and vitamin D 400 IU once daily.
As reported in European Urology, the mean spine BMD increased by 1.7% from baseline in the alendronate group, compared with a 1.9% decrease from baseline in the placebo group. Similarly, the mean total hip BMD increased by 0.7% in the alendronate group while it decreased by 1.6% in the placebo group.
The team also observed significantly greater improvements in markers for bone desorption as well as for bone formation and turnover.
The bone resorption marker, cross-linked N-telopeptide of type I collagen (Ntx), was decreased by a median of 3.5% in the alendronate group and increased by a median of 16.5% in the placebo group. Baseline urinary Ntx was also a significant predictor for loss of BMD.
Furthermore, bone-specific alkaline phosphatase, a marker of bone formation and turnover, was decreased by a median of 2.25% in the alendronate group and increased by a median of 3.12% in those who took placebo.
"Previous epidemiologic studies have suggested that high bone turnover is an independent risk factor for osteoporotic fractures," note Klotz and colleagues.
"Because loss of BMD in the ADT setting is associated with an increased fracture risk that is not mitigated by oral calcium and vitamin D supplementation, oral bisphosphonate therapy may have a role in men initiating androgen deprivation," concludes the team.
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