Breast Cancer Risk Lower for Older Women With Weak Bones
June 19, 2001 - Women at the highest risk of osteoporosis have a lower risk of breast cancer than their strong-boned peers.
A report in the Journal of the National Cancer Institute finds that women 65 and older with the lowest bone-mineral density have a threefold lower risk of breast cancer than women with the highest bone density. And for more advanced tumors, the weak-boned women have a 5.6-fold lower risk.
"Should people be concerned about too high bone density? Absolutely not," study co-author Jane A. Cauley, DPH, tells WebMD. "What we want people to understand is that there is a relationship between lifetime [indicators] of bone-mineral density and breast cancer. Somehow this is even stronger for advanced stages of breast cancer -- maybe estrogen makes these kinds of cancer grow faster. But this doesn't mean women need to worry about having strong bones."
Both breast-cancer cells and bone cells grow better when they have lots of estrogen around. But after following almost 9,000 originally cancer-free women aged 65 or older for 6 1/2 years, Cauley and colleagues don't think that the findings mean women should abandon hormone-replacement therapy with estrogen.
"I don't think women should worry about their hormone therapy," says Cauley, who is director of the epidemiology of aging program at the University of Pittsburgh. "I think this is just further documentation that estrogen does play a role in breast cancer. Right now it is interesting from the point of view of learning the role estrogen plays in breast cancer, but at this time it can't be translated into a clinical message."
Joan A. McGowan, PhD, director of the musculoskeletal diseases branch, of the National Institute of Arthritis and Musculoskeletal and Skin Diseases, is very familiar with this research.
"This is about lifetime exposure to estrogen and all kinds of other influences on both bone and breast cancer," McGowan tells WebMD. "Women might ask, 'Well, gee, if I have good bones will I be putting myself at risk of breast cancer?' I answer by saying that it is a fact women with a college degree have a higher risk of breast cancer. But this is no reason not to let your daughter go to college. Right now there is not anything women should do to change their behavior."