The combined effects of chemotherapy and endocrine therapy may increase the risk of bone fractures in breast cancer survivors. In a study scheduled for publication in the April issue of the Archives of Physical Medicine and Rehabilitation, researchers from the Oregon Health & Science University Knight Cancer Institute, Portland, asked post-menopausal breast cancer survivors whether they had fallen in the past year and then tracked their falls over a six-month study period. They found evidence that women who have survived breast cancer may fall more often than their peers.

"Our study is the first to consider how breast cancer treatment may increase fall risk by using a comprehensive set of objective measures of fall risk and by exploring mediators of the treatment-falls relationship," commented Kerri M. Winters-Stone, Ph.D., Associate Professor and Associate Scientist, Oregon Health & Science University, School of Nursing and a member of the Knight Cancer Institute. "Our findings suggest that recently treated postmenopausal breast cancer survivors have higher rates of falling compared with population averages for community-dwelling older adults. Balance disturbances may explain how treatment could have contributed to falls in breast cancer survivors."

Investigators found that 58% of breast cancer survivors had experienced a fall in the previous year and almost half (47%) fell within 6 months after joining the study, a rate nearly double the 25% to 30% annual fall rate reported for community-dwelling older adults over 65 years of age.

Researchers measured a comprehensive set of neuromuscular and balance characteristics known to be associated with falls in 59 study participants. They found that only balance discriminated breast cancer survivors who fell from those who did not. The study findings also suggest that the balance problems may have been related to changes in the vestibular system that were associated with chemotherapy treatment.

Professor Winters-Stone stated, "Falls in breast cancer survivors are understudied and deserve more attention, particularly in light of the increase in fractures after breast cancer treatment and the relationship of falls to fractures. Our findings add to growing evidence that fall risk is increased in breast cancer survivors and that vestibular function may underpin associations between breast cancer treatment and falls."