Breast Cancer Survivors May Face Broken Bones
Risk of Bone Fractures Higher Among Postmenopausal Breast Cancer Survivors
March 14, 2005 -- Breast cancer survivors may face a higher risk of broken bones compared with other women of the same age, a new study shows.
Researchers found that the rate of bone fractures was consistently higher among postmenopausal women who had been treated for breast cancer than for other women in the same age group for all types of fractures except hip fractures.
For example, breast cancer survivors had a 36% higher risk of a broken wrist or forearm, and 31% higher risk for all other types of fractures except hip fractures.
Researchers say smaller studies have shown lower bone density -- a sign of weak bones -- and accelerated bone loss among postmenopausal breast cancer survivors, but this is the first large study to show a higher rate of bone fractures among breast cancer survivors.
The results appear in the March 14 issue of the Archives of Internal Medicine.
Breast Cancer May Affect Women's Bones
In the study, researchers compared the number of broken bones reported during a five-year period in a group of more than 5,000 women who had been treated for breast cancer and 80,000 women with no history of breast cancer.
The study showed that breast cancer survivors had a higher rate of vertebral (back bone), lower arm or wrist, and all other fractures, except for hip, compared with the other women. Overall, breast cancer survivors have an additional 68.6 more fractures per 10,000 people each year compared with women without breast cancer.
In addition, researchers found that the risk of vertebral fractures was particularly high among breast cancer survivors (78% higher). Researchers say the bones of the back (vertebrae) are extremely sensitive to hormonal changes, and women under age 55 are more likely to experience a dramatic decline in estrogen levels due to breast cancer-related chemotherapy treatment.
Researchers say the increased risk of broken bones persisted even after adjusting for menopausal hormone therapy use. Hormone therapy has been used for the prevention of osteoporosis. It has been shown to reduce bone loss and reduce the risk of fractures.
Eight percent of breast cancer survivors and 47% of women without breast cancer reported using hormone therapy. Even after taking into account HRT use, women with breast cancer still had a higher risk of fractures.
The study shows that the lower use of HRT in breast cancer survivors was not the cause of increased fractures.
No difference in fracture risk was found for hip fractures. The researchers say this may be largely due to the low number of hip fractures that occur before the age of 70.
Researchers say if these results are confirmed by additional studies, the number of excess fractures may be as high as 13,000 per year for the 2 million postmenopausal breast cancer survivors in the U.S., and strategies will be needed to reduce the number of broken bones among breast cancer survivors.