Men with a high risk of bone fracture who are receiving long-term androgen deprivation therapy (ADT) for prostate cancer have a higher fracture incidence after their treatment is completed. Also, men who experienced a fracture had a 1.38-fold higher mortality risk than those who did not.
Men with localized prostate cancer who have underlying health conditions often receive ADT with the hope to shrink or delay growth of their tumor, since they are considered inappropriate candidates for more aggressive therapies such as surgery or radiation. The receipt of ADT for prostate cancer has previously been linked to an increased risk of bone fracture and other skeletal complications, such as a decrease in bone mineral density. This study 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, researchers reviewed information on demographics and tumor characteristics from 75,994 men age 66 years and older with localized prostate cancer from 1992 to 2007. The research team created a risk assessment scale for baseline skeletal complications, including fracture. The scale utilized the presence of certain conditions within 1 year prior to cancer diagnosis, including diabetes, alcohol and cigarette use, paralysis, and liver disease.
Investigators found that during a 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%). 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 Grace Lu-Yao, PhD, MPH, of The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, and UMDNJ-School of Public Health. “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 was not examined. Despite these limitations, Lu-Yao said, their investigation shines new light on a large subset of men who commonly receive ADT. This study was published in BJU International (2013; doi:10.1111/j.1464-410X.2012.11758.x).