The real-world fracture risk in men who are treated for advanced prostate cancer is much higher than what has been reported in randomized controlled trials, according to a recent study from Thomas Jefferson University researchers. The findings were published in the Journal of the National Cancer Institute.
Many men who take androgen receptor pathway inhibitors (ARPI) for advanced prostate cancer have osteoporosis or a history of fractures, which increases future fracture risk. But men with these preexisting conditions are typically excluded from randomized controlled trials, so the data doesn’t accurately depict real-world patient experiences.
Jefferson researchers used Surveillance, Epidemiology, and End Results (SEER)-Medicare registries to identify 10,463 men with advanced prostate cancer treated with ARPI (abiraterone acetate with prednisone or enzalutamide) between 2013 and 2020. They found that men without a fracture history who took ARPI for advanced prostate cancer had a 28% to 30% risk of fracture over three years. Among men with a fracture history before ARPI, three-year fracture risk exceeded 50%. Meta-analysis from randomized controlled trials showed a much lower fracture risk, 2% to 11%, for men who took ARPI.
“If you’re a patient, you may think, a 2% fracture risk is not too bad if you can control the cancer,” says Grace Lu-Yao, PhD, MPH, the study’s first author. “But a 50% fracture risk may change your mind about pursuing that treatment.”
The study revealed the fracture risk among men with prior fracture risk remained high (above 44%) despite bone health agents.
“This suggests we have to identify high-risk patients much earlier, even before they need ARPI,” says Dr. Lu-Yao.
Because more prostate cancer patients are starting ARPI at an earlier stage in their disease, fracture prevention becomes even more important.
“ARPI were initially approved for patients with late-stage prostate cancer, but now they are used by patients with more than 10 years of life expectancy,” says Dr. Lu-Yao, a Sidney Kimmel Medical College faculty member. “You will want to consider the risk of fracture if you still have a long time to live.”
The study findings could help patients and clinicians to make more-informed shared decisions about their cancer therapy. Postdoctoral researchers Amy Shaver, PhD, PharmD, MPH, and junior faculty Nikita Nikita, MD, MPH, were involved in the study.
By Lisa Fields