Common treatment for prostate cancer is putting men at higher risk for fractures

30/09/2010

Men with prostate cancer are often treated with hormone therapy otherwise known as Androgen Deprivation Therapy (ADT). New research from the Institute for Clinical Evaluative Sciences (ICES) and the University Health Network in Toronto shows that ADT increases the risk of fractures.

“Patients and doctors need to be aware of the risk associated with this treatment,” says Dr. Shabbir Alibhai, principal investigator and researcher at the University Health Network.

Researchers have identified several important, easily clinically identifiable risk factors that increase fracture risk. This information should supplement a bone mineral density test, which should be done at baseline in all men starting any form of ADT (intermittent or continuous).

The study of 19,079 Ontario men 66 years old or older with prostate cancer with at least six months of continuous ADT or bilateral orchiectomy with men with prostate cancer who had never received androgen deprivation found:

At a mean 6.47-year follow-up ADT was associated with a 65 per cent relative increase in risk of fragility fracture and a 45 per cent relative increase in risk of any fracture
Independent predictors of fragility and any fracture were increasing age, prior bone thinning medications, chronic kidney disease, prior dementia, prior fragility fracture and prior osteoporosis diagnosis or treatment
Continuous androgen deprivation therapy for at least six months is associated with an increased risk of fracture. Increasing age, prior osteoporotic fracture and dementia are important clinical factors that may warrant greater consideration of anti-osteoporotic therapy in these men

“Too few men are getting routine bone mineral density testing done and too few men are being advised to do relatively simple things such as take calcium, vitamin D and engage in light weight-bearing exercises to help their bones,” says Alibhai. “Our data show that fracture risks with ADT are not only real but they affect bones throughout the body, not just the bones one typically associates with osteoporosis and fragility fractures like the spine, hip and wrist.”

Researchers recommend that all men starting ADT should:

Supplement with calcium and vitamin D in order to reduce fracture risk
Have prescription therapies (a bisphosphonate, denosumab, or toremifene) tailored to their risk for fracture, which is based on clinical risk factors (including age) and bone density results

Authors: Alibhai S, Duong-Hua M, Cheung AM, Sutradhar R, Warde P, Fleshner NE, Paszat L.

The study “Fracture types and risk factors in men with prostate cancer on androgen deprivation therapy: a matched cohort study of 19,079 men,” is in the September issue of The Journal of Urology.

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.