Studies of Bone Health and Breast Cancer
Reviewed studies: "Limited bone loss with two years on and one year off Aromasin", "Zometa improved bone strength in Femara users after one year", "Oral clodronate maintains bone mass in women with advanced breast cancer", American Society of Clinical Oncology Annual Meeting, May 2005, Abstracts #531, #533, #555
Limited bone loss with two years on and one year off Aromasin (Abstract #531)
For 57 post-menopausal women with early-stage breast cancer, taking Aromasin (chemical name: exemestane) for two years did not cause significant loss of bone mineral density (BMD) in the lower back and caused only small (but significant) BMD loss in the top of the upper leg bone. These women were compared to 64 women who took a placebo (a fake pill) instead of Aromasin. The BMD measurements were taken during treatment and one year after the women had stopped treatment.
Zometa improved bone strength in Femara users after one year (Abstract #533)
For post-menopausal women with early-stage breast cancer taking the aromatase inhibitor Femara (chemical name: letrozole), using Zometa (chemical name: zoledronic acid) resulted in improved bone mineral density (BMD) at the spine and hip after one year.
Zometa is an intravenous bisphosphanate—a drug that helps slow bone loss and rebuild bone strength in post-menopausal women. The 170 women who used Zometa immediately were compared to 173 women whose use of Zometa was delayed. Those women lost BMD at the spine and hip after one year. The differences in BMD measurements between the two treatment groups were statistically significant, meaning that they were likely due to when Zometa was used and not just to chance.
Oral clodronate maintains bone mass in women with advanced breast cancer (Abstract #555)
For 243 women with advanced breast cancer (cancer that has spread beyond the breast and underarm lymph nodes), taking oral Bonefos (chemical name: clodronate) for two years significantly increased bone mineral density (BMD) at the spine and hip. In comparison, the 255 women who took a placebo (a fake pill) lost BMD at the spine and hip.
Women with advanced breast cancer can have several problems related to bone loss. First, if cancer spreads to the bone, it can create holes, making the bone weak and at increased risk of fracture. Second, some treatments for breast cancer can cause bone loss. These include medicines that shut down the ovary and its production of estrogen, such as Zoladex (chemical name: goserelin) and Lupron (chemical name: leuprolide), as well as aromatase inhibitors. Finally, chemotherapy can cause early menopause in pre-menopausal women—and the associated drop in estrogen leads to bone loss.
What breastcancer.org says about this article…
Studies of Bone Health and Breast Cancer
Abstract #531: This early report is important because Aromasin is an aromatase inhibitor, a class of drugs that has been shown to increase the risk of bone loss. The amount of bone loss in any individual woman—taking any similar medicine—should be monitored carefully.
Abstract #533: The early results of this study are important because effective measures are needed to minimize possible bone loss associated with use of aromatase inhibitors. This five-year study will eventually provide more information on the longer-term effectiveness of Zometa.
Abstract #555: This study is helpful because the results show that oral—and not just intravenous—forms of bisphosphonate can reduce bone loss associated with breast cancer and its treatments. The Food and Drug Administration has not yet approved Bonefos for use in the United States, but it is approved for use in many other countries.