COPENHAGEN, Denmark—Men with prostate cancer treated with orchidectomy or  androgen deprivation are at increased risk for fractures particularly of the hip, according to a retrospective cohort study in the October issue of the British Journal of Urology.¹

"The risk of hip fracture is not confined to the very old, neither is the risk made negligible by the excess mortality in patients with advanced prostate cancer," said lead author Bo Abrahamsen, MD, PhD, of Copenhagen University Hospital Gentofte in Demmark.

Dr. Abrahamsen reported that overall fracture risk "was doubled in men with prostate cancer" and that the increased risk "was apparent early after diagnoses and remained pronounced even in long term survivors."

Danish registry highlights fracture risk

The researchers analyzed data from the Danish National Hospital Discharge Register, the National Bureau of Statistics, and the National Prescriptions Database on 15,716 men aged >50 years who presented with a fracture at any hospital in Denmark in 2000 and 47,149 age-matched controls. They found that 1.3% of control patients and 2.5% of those patients with fracture had a previous diagnosis of prostate cancer. Overall, 3.1% of hip fractures in Danish men aged >50 years are attributable to prostate cancer.

Men with prostate cancer had a 1.7-fold increased risk of sustaining any fracture and a 3.7-fold increased risk of sustaining a hip fracture, the study showed.

Risk of hip fracture was increased among men of all ages. In particular, men aged 50 to 65 were eight times more likely to experience a hip fracture than would have been expected given their age and previous fracture history.

There was no increased risk of vertebral fractures among men with prostate cancer. "This was unexpected, in view of the high prevalence of such fractures in male osteoporosis, but not when considering the subclinical presentation of most vertebral fractures, the restriction in access to radiography in patients with back pain, and the ensuing high prevalence of undiagnosed vertebral deformities in men," the study authors write.

Androgen deprivation therapy added to the overall fracture risk with an odds ratio of 1.7 (P <.01) as did orchidectomy with an odds ratio of 1.7 (P <.01). After researchers controlled for previous fracture, prostate cancer, and age, the study showed use of androgen deprivation therapy was associated with an odds ratio of 1.7 for hip fractures and 1.9 for all fractures.

Evaluate bone density in men with prostate cancer

"The treatment for prostate cancer, which gets rid of testosterone production through one or another mechanism, is associated with bone loss and fracture risk," said Ethel S. Siris, MD, the Madeline C. Stabile professor of clinical medicine and director of the Toni Stabile Osteoporosis Center at Columbia University Medical Center in New York City. "We have all agreed that such men need bone density testing when they initiate therapy with these antiandrogen treatments for prostate cancer," she told CIAOMed.

What happens next depends on their bone density, she said. "If their bone density is excellent, you might simply monitor the guy and see what happens to his bone density over time. On the other hand, if an older man has low bone density at the time he is about to begin therapy, that might lower it further, and most people would argue that a bisphosphonate should be used," Dr. Siris concluded.

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