Previous evidence has suggested that cancer survivors are at a higher risk of cancer compared to people without a history of cancer. But the research on the factors that increase or might contribute to that increased risk of bone fractures is limited. It's also an important endpoint to study when it comes to improving quality of life for cancer survivors, noted Erika Rees-Punia, PhD, MPH, Senior Principal Scientist in Epidemiology and Behavioral Research at the American Cancer Society. Bone fractures, particularly those of the pelvis and spine, can cause a lot of issues down the line, she said. "They're really more than just a broken bone."
Bone fractures increase health care costs, may limit mobility, and may even increase the risk of premature death, some studies have suggested (JAMA 2009; doi:10.1001/jama.2009.50). Rees-Punia and her colleagues conducted a study that analyzed associations between cancer diagnoses (including time since diagnosis and cancer stage at diagnosis) with risks of pelvic, radial, and vertebral fractures (separately and combined) among older cancer survivors, and compared those findings with fracture risk among older adults without a history of cancer. They also analyzed the differences in risk of fracture stratified by modifiable behaviors, treatment, and cancer type. The data were published online ahead of print in JAMA Oncology (2022; doi: 10.1001/jamaoncol.2022.5153). In this article, Rees-Punia explains what the data showed and their clinical implications.
1 What were the key findings from your research and do they align with other studies that have looked at these questions?
"We found that older cancer survivors, especially survivors who were more recently diagnosed or who had a history of receiving chemotherapy, had a much higher risk of both hip and spinal fractures than older adults without a history of cancer. And we found that that risk was elevated for at least 5 years post-diagnosis and post-treatment. Then we also saw that smoking was associated with a higher risk of bone fractures, and there was also some suggestion that physical activity might be associated with a lower risk of fractures.
"The risk of fractures in cancer survivors has definitely been studied before. But previous studies really focused on one cancer type, most often breast cancer. They often combined fracture sites together, even though we know that certain sites like the hip and the spine are more costly and they're more likely associated with complications down the road. And other studies have focused on cancer survivors immediately after their treatment. So, we included survivors of many different cancer sites. We also explored the differences in fracture risk by site. And then we also followed cancer survivors for over 15 years.
"There was definitely some existing evidence [before our research] that suggested cancer survivors might be at higher risk of bone fractures. That might likely be because of higher rates of osteoporosis coupled with low muscle mass. It could also potentially be because of balance issues, unexpected changes in gait, or unexpected changes in body composition. All these things are likely associated with chemotherapy. So, that evidence did exist, but there were some limitations to the studies that were out there before this one."
2 What are the implications of this data? Does any of the research inform clinical practice?
"Based on our results, it is reasonable to suggest that a cancer survivor who may be worried about their excess risk for fractures could focus on health behaviors, including becoming (or remaining) physically active and quitting (or continuing to stay away from) smoking.
"Ideally, that would include things like smoking cessation programs or referrals for physical activity with cancer exercise professionals who can counsel individuals on how to be physically active in ways that are appropriate and safe for them, because yes, they are at higher risk, especially soon after diagnosis. So, the action item here is cancer survivors may be able to lower their risk of bone fractures through their health behaviors."
3 What are the next steps of this work and further questions that need to be answered?
"Our findings around physical activity were interesting and we have plans to explore the associations with both aerobic exercise and strength training-two different types of exercise. Our future research will look at the associations of these health behaviors across the lifespan with fracture risk in cancer survivors. In the current study, we only had one time point of physical activity and smoking, which was assessed pre-diagnosis for cancer survivors.
"An interesting question a cancer survivor might have: 'I was completely physically inactive before my diagnosis; if I were to become more active after my diagnosis, could I still reduce my risk of bone fractures?' This is something we hope to better understand with our future research.
"Really understanding what factors might be associated with a reduced risk of fractures in cancer survivors is important. We do hope that the results will impact the guidance that clinicians will provide cancer survivors. We think that could include smoking cessation programs and referrals for physical activity with cancer exercise professionals."