“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.
More detailed study findings on the ICES website: www.ices.on.ca
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