The study included 112 men with prostate cancer with an average age of 71. After an average of two years of androgen deprivation therapy for prostate cancer, only 9% of the men had normal bone mass, while 52% had low bone mass and 39% developed osteoporosis.
To study the effect of alendronate on these men, they were randomized into two groups to receive either alendronate once a week through an orally administered pill or a placebo.
At one year follow-up, bone mass in the spine and hip increased significantly in the men treated with alendronate, by 4.9% and 2.1% respectively. By comparison, men in the placebo group had significant losses of bone mass in the spine and hip, of 1.3% and 0.7% respectively. In addition, the therapy was well-tolerated and easily administered.
“Since most men with prostate cancer remain on androgen deprivation therapy for an indefinite amount of time, bone loss can be a serious and long-term side effect from therapy,” said Dr Joel Nelson, co-author of the study and professor and chairman of the department of urology at the University of Pittsburgh School of Medicine. “With more than 230,000 men being diagnosed with prostate cancer each year, the addition of alendronate therapy could help to prevent the incidence of debilitating bone fractures.”
Androgen deprivation therapy works by depriving the body of testosterone, an androgen hormone that increases the growth of prostate tumors. However, testosterone is also essential to maintaining bone mass in men. While doctors have been using this type of therapy for more than a decade to treat men with late-stage metastatic prostate cancer, they have begun using it more recently in men with earlier-stage disease and for longer periods of time; this increased exposure increases the risk for developing osteoporosis.
The study results were presented at the American Society of Clinical Oncology Prostate Cancer Symposium in San Francisco.