The rate of prescribing bisphosphonates to protect the bone health of prostate cancer patients taking androgen deprivation therapy is extremely low in Ontario, even among those at high risk of fracture, according to a research letter published online Dec. 2 in JAMA.

Canadian guidelines have recommended bisphosphonates for men at risk for bone fracture since 2002, and specifically for men taking androgen deprivation therapy (ADT) since 2006. However, prescribing patterns for these agents are relatively unknown, said Dr. Husayn Gulamhusein of University Health Network, Toronto, and his associates.

The investigators assessed rates of these prescriptions over time by analyzing data in an Ontario cancer registry regarding 35,487 men aged 66 years and older who initiated ADT for prostate cancer between 1995 and 2012. They found that bisphosphonate prescriptions were filled for only 0.35/100 men in the earliest years of the study period, a rate that rose to only 3.40/100 men in the final years. “Even among those with prior osteoporosis or fragility fracture, rates remained low,” the researchers said ( JAMA 2014;312:2285-6 ).Their findings indicate “limited awareness among clinicians regarding optimal bone health management,” they added.

There was a decrease in bisphosphonate prescriptions after 2009, which “may be partly due to negative media regarding the association of bisphosphonates with rare osteonecrosis of the jaw and atypical femoral fractures. This is appropriate for groups at low risk for fractures, but the decrease in use for high-risk patients is concerning,” Dr. Gulamhusein and his associates noted.