NEW YORK (Reuters Health) - Testosterone-lowering therapy —— one of the most effective and commonly used therapies for prostate cancer —— often causes bone loss. However, once-weekly drug treatment combats the problem, according to a new study.

　　Fosamax, used to treat osteoporosis in postmenopausal women, also helps prevent bone loss associated with so-called "androgen deprivation" treatment of prostate cancer, the researchers reported at the 2006 Prostate Cancer Symposium.

　　"Patients on androgen deprivation therapy tend to lose bone mass early, within the first 6 to 12 months of treatment, and the bone loss continues for the duration of therapy," noted Dr. Susan L. Greenspan from the University of Pittsburgh.

　　"Currently," Greenspan noted, "lifelong androgen deprivation therapy is common for advanced prostate cancer, but more recently it has been a common treatment for less aggressive disease."

　　Bone mass, she said, "should be evaluated in men who are starting therapy to lower testosterone because we are putting them in a situation similar to newly postmenopausal women with a relatively fast rate of bone loss."

　　In a 2-year study sponsored by the National Institutes of Health, Greenspan and colleagues are evaluating the effects of Fosamax on bone in a group of men with prostate cancer receiving androgen deprivation therapy.

　　In the ongoing study —— now in its second year —— 112 men are receiving calcium and vitamin D supplementation and half of them are also taking weekly Fosamax. Greenspan presented 1-year data from a planned interim analysis.

　　At the start of the study, "only about 10 percent of men had normal bone mass," Greenspan said. "The average duration on androgen deprivation therapy was only about 22 months or roughly 2 years, but 90 percent of them did not have normal bone mass; in fact 39 percent had osteoporosis by WHO criteria."

　　After 1 year, bone mass increased by 4.9 percent in the spine and by 2.1 percent in the hip among men on Fosamax, compared with decreases of 1.3 percent in the spine and 0.7 percent in the hip among men on placebo.

　　"Once weekly oral (Fosamax) should be considered to prevent this bone loss and prevent the occurrence of osteoporosis and fractures," Greenspan concluded.

　　The 2006 Prostate Cancer Symposium is co-sponsored by the American Society of Clinical Oncology, the American Society for Therapeutic Radiology and Oncology, the Prostate Cancer Foundation, and the Society of Urologic Oncology