Higher fracture rate seen in some ADT patients

New research shows that men with a high risk of bone fracture who are undergoing long-term androgen deprivation therapy (ADT) for prostate cancer have a higher fracture incidence following treatment completion.

The findings, which were published online in BJU International (Jan. 17, 2013), also show that men who experienced a fracture had a 1.38-fold higher mortality risk than those who did not.

Previous studies have shown an association between the receipt of ADT for prostate cancer and an increased risk of bone fracture and other skeletal complications, such as a decrease in bone mineral density. Investigators at the Cancer Institute of New Jersey and Robert Wood Johnson Medical School, New Brunswick, NJ, further explored the impact of this treatment on men already deemed to be at high risk for fracture prior to receiving therapy.

Using the population-based Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database, the authors reviewed information on demographics and tumor characteristics from 75,994 men aged 66 years and older who were diagnosed as having localized prostate cancer from 1992 to 2007. A risk assessment scale for baseline skeletal complications-including fracture-was created, utilizing the presence of certain conditions within 1 year prior to cancer diagnosis. These conditions included diabetes, alcohol and cigarette use, paralysis, and liver disease.

The authors found that during 12-year follow up, more than 58% of men deemed at high fracture risk prior to treatment and 38% considered at low risk developed at least one fracture following ADT. The research also showed that men with a high baseline risk had a higher probability of receiving ADT (52.1%) compared to those with a low baseline risk (38.2%). It was also determined that those men receiving ADT by itself were likely to have a stronger dose than those who received ADT in combination with other treatments for their prostate cancer. Mortality risk was found to be 40% higher within 2 years after experiencing a fracture.

"Our findings suggest that treating men having a high baseline risk of fracture with long-term androgen deprivation therapy may have serious adverse consequences," said senior author Grace Lu-Yao, PhD, MPH. "We anticipate the results of this study will prompt further examination of a patient’s baseline risk of fracture and skeletal complications prior to administering this course of therapy."

The authors note the use of bisphosphonates, which are effective in preventing bone loss in patients with prostate cancer receiving ADT, was not available in the SEER-Medicare linked data. Information regarding a patient’s height and weight, which can be considered risk factors for skeletal complications, also was not available. Data on men younger than 66 years of age were not examined. Despite these limitations, Dr. Lu-Yao said their investigation shines new light on a large subset of men who commonly receive ADT.