FRIDAY, March 4 (HealthDay News) -- Breast cancer survivors may be at increased risk for falls and broken bones due to the combined effects of chemotherapy and endocrine therapy, a new study suggests.

Researchers looked at 59 postmenopausal breast cancer survivors, and found that 58 percent of them had experienced a fall in the year before the start of the study and 47 percent had a fall during the six-month study period.

Those rates are much higher than the 25 percent to 30 percent annual fall rate reported for community-dwelling adults over 65 years old, noted Kerri M. Winters-Stone, an associate professor and associate scientist at Oregon Health & Science University (OHSU) School of Nursing, and colleagues.

Balance was the only difference between breast cancer survivors who fell and those who did not. The researchers said their findings also suggest that balance problems may be due to chemotherapy-related changes in the vestibular system, which is involved in balance and spatial orientation.

The study is scheduled for publication in the April issue of the Archives of Physical Medicine and Rehabilitation.

"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," Winters-Stone, who is also a member of the OHSU Knight Cancer Institute in Portland, said in a journal news release.

"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," she added.

More information

Learn more about balance from the Vestibular Disorders Association.