Research for Survivors

Breast Cancer Survivors: Take Care to Preserve Bone Strength

While many women worry about keeping their bones strong and stable as they age, survivors of breast cancer may need to take special care to preserve bone health and strength, say health experts.

New research from the University of Arizona, Tucson has used data from the Women's Health Initiative Observational Study (WHI-OS) to draw conclusions about the effects of living through breast cancer on bone density.

The research, published in Archives of Internal Medicine, found that postmenopausal breast-cancer survivors may have a higher risk of fractures in bones excluding the hip bone than their counterparts who have not undergone breast-cancer treatments.

The study was conducted by Zhao Chen, Ph.D., M.P.H. and colleagues at the University of Arizona. The team compared bone fracture rates in a group of 5,298 women who had breast cancer with a group of 80,848 women who had no history of breast cancer over a five-year period. Women gave information on their fracture histories in questionnaire form, and the fractures were placed into four categories: hip, forearm/wrist, spine or back, and other fractures.

Chen and colleagues found that aside from hip fractures, which seemed to occur with the same frequency in both groups, "fracture rates were higher in the breast-cancer survivors than in the reference group. Overall, breast-cancer survivors may sustain 68.6 excess fractures per 10,000 person-years compared with other women in the same age group."

A person-year is defined as the number of the persons multiplied by the number of years of observation.

The researchers adjusted the figures to account for other risk factors, including medication use, hormone replacement therapy, prior history of fractures and lifestyle, but found that the increased risk held true in spite of these adjustments, suggesting a likely correlation between breast-cancer survival and bone fractures.

Previous studies involving smaller populations have found that postmenopausal breast cancer survivors suffer from accelerated bone loss after chemotherapy for breast cancer and have low bone density, but findings on fracture risk have been inconsistent.

With further research, noted the authors, "the excess number of fractures may be as high as 13,000 per year for the two million postmenopausal breast cancer survivors in the United States." They concluded "more research is needed to understand the fracture risk in this special population and to develop strategies to reduce the number of fractures among breast-cancer survivors."

References:
Chen Z, Maricic M, Bassford TL et al. Fracture risk among breast-cancer survivors: results from the Women's Health Initiative Observational Study. Arch Intern Med. 2005 Mar 14;165(5):552-8.