Bone Scan for Osteoporosis Helps Diagnose Breast Cancer

Dual Energy X-ray Absorptiomety (DEXA) Scan bone density tests are typically done to determine the likelihood of losing bone mass (osteopenia) or diagnosing osteoporosis. A T-score of -2.5 or less would indicate osteoporosis.

Bone density testing takes only a few minutes to perform and is non-invasive. The scan is a very quick and easy test and is routinely done in most post-menopausal women. The DEXA Scan uses only a very small amount of radiation to measure bone mineral density and predict the chances of future bone fractures. The test is done while the woman is fully clothed, although nothing metal is allowed, so sweat pants or slacks with an elastic waistband are best.

Recently a second diagnostic determination has been found for the DEXA Scan. It has been discovered that a bone density test could also be used to help identify markers for women who are more likely to develop breast cancer. Studies done by Eli Lilly & Company, the University of Arizona at Tucson and at the University of Pittsburgh Medical Center all suggest that bone mineral density is a marker of the body's response to estrogen. It was found that women with higher bone density appear to be more sensitive to the hormone's effects than women with lower bone density.

Science Daily says, "Studies have found an association between higher bone mineral density and higher breast cancer risk, and bone mineral density tests have been proposed as a potential addition to breast cancer risk models. This study, supported by Eli Lilly & Company, is the first to investigate the relationships among bone mineral density, traditional breast cancer risk assessment tool results, and breast cancer incidence among the same group of postmenopausal women".

To further follow up on these studies, Dr. Zhao Chen did an eight year study of 10,000 post-menopausal women, which found that women with a higher bone density were twice as likely as develop breast cancer.

"What we're showing in the study is that bone density may be an indicator or a marker of something else which may link to breast cancer risk," Zhao Chen, Ph.D., M.P.H., an epidemiologist at the University of Arizona in Tucson.

Another study, led by Dr. Jane Cauley and done at the University of Pittsburgh Medical Center, followed more than 8900 women over age 65 who were without breast cancer. After six years, it was found that women with the highest bone mineral densities tended to develop breast cancer. During the six year study, 315 of these women developed breast cancer. Bone density was done at three sites: wrist, arm and heel. After adjusting for other risk factors for breast cancer such as age and obesity, it was found that women with the highest bone density in all 3 sites was 2.7 times greater than women with lowest bone density measurements.

Conclusions of these studies suggest an association between osteoporosis and invasive breast cancer, which could mean that a bone mineral density test may well become a routine diagnostic tool for earlier breast cancer detection as well as diagnosing osteoporosis.

Sources:

http://www.sciencedaily.com/releases/2008/07/080728081346.htm

http://www.ivanhoe.com/channels/p_channelstory.cfm?storyid=19810

http://www.bmj.com/cgi/content/full/322/7302/1566/d