Bone mineral density, a measure of bone thickness, decreases during the first 2 years of androgen deprivation therapy in men with prostate cancer. Androgen hormones, such as testosterone, stimulate prostate tissue and can accelerate the growth of any prostate cancer. Androgen deprivation, with drugs or surgery, can reduce this stimulation. Bone density measurement before beginning androgen deprivation therapy is important, because about 20 to 30 percent of these patients will have osteoporosis, a bone-thinning disease. It is important to know the health of bone in prostate cancer patients in order to prevent bone fractures, which are a bad prognostic factor for survival. Researchers from the Vall d'Hebron Hospital, Autonoma University School of Medicine, Spain, evaluated the dynamics of bone mineral density in the spine and hip over a 2-year period in 62 men with prostate cancer. Men receiving androgen deprivation therapy experienced bone mineral density losses ranging from 2 to 6 percent after 12 months, whereas bone mineral density did not change significantly in men not on androgen suppression. At 24 months, however, there was evidence that the bone loss had slowed down. The area that best reflected the androgen deprivation-induced bone loss was in a region of the hip called Ward's triangle. Many physicians have used simple forearm bone scans, which can be quickly and easily obtained in their office. This report suggests that this may not accurately reflect the greatest extent of bone loss, which may lead to a delay in appropriate treatment. 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.
The Journal of Urology,
May 2006