Prostate cancer could also lead to bone fracture, say scientists at the Garvan Institute of Medical Research, Australia.
Analysis of data from Garvan's Dubbo Osteoporosis Epidemiology Study suggests that men with prostate cancer face a 50 per cent higher risk of fracture. And the risk doubled in the case of those who undergo androgen deprivation therapy (ADT), according to the Institute's press release.
The results have just been published online in the prestigious international journal Bone
"This is a controversial area which has been under discussion for at least three years," said Garvan's Associate Professor Tuan Nguyen, who initiated the study after hearing speculation on the concept. "It has taken us about two years to assemble and analyse the data. The results suggest a link between the two diseases, although we still don't understand the mechanisms."
Professor Nguyen and his colleagues have studied 822 men from Dubbo for nearly 20 years. These men were all aged 60 or over in 1989 when the study began. Of the 822 men, 43 subsequently developed prostate cancer.
Twenty-two of the men received ADT (androgen deprivation therapy) and 21 did not. Compared to the men without prostate cancer, those with the disease showed a 50 per cent increase in the risk of fracture. For those being treated with ADT, the risk increased approximately twofold.
(Androgen deprivation therapy is aimed at eliminating testosterone from the body as the hormone stimulates growth of prostate cancer cells.)
"The results have important implications in practice for several reasons," said Nguyen. "First, most of the men who developed prostate cancer started out with a higher BMD (bone mineral density) than average. Second, developing prostate cancer clearly increased their risk of fracture. Third, ADT treatment doubled their risk of fracture."
"There are factors at play that we do not yet understand. Obviously the higher BMD of the men with prostate cancer did not protect them against fracture. Exactly what mechanisms are at work are unclear."
"Osteoporosis in men often remains untreated, even after a fracture. It is highly unlikely, therefore, that any of the men at higher risk will be receiving anti-fracture therapy."
"The clear message that comes out of this study is that men with prostate cancer should consider seeking evaluation for osteoporosis, particularly if they are being treated with ADT."
"More and more we are seeing ways in which diseases are connected. You can't isolate osteoporosis from cancer from diabetes and so on. In treating one disease, we must be careful not to increase the risk of another. As we understand these connections, we learn how better to treat the whole person."