August 21 (HealthDay News) -- The osteoporosis drug Zometa (zoledronic acid) prevented bone loss at 12 months in premenopausal women undergoing chemotherapy after they had surgery for early stage breast cancer, a new study found.

The multicenter, phase III study is the first to evaluate the use of zoledronic acid in premenopausal breast cancer patients. The 101 women (85 completed the study) were divided into two groups that received either zoledronic acid or a placebo every three months for one year. All the women were given oral vitamin D and calcium supplements.

Bone mineral density (BMD) was measured before the start of chemotherapy and again at six and 12 months. At six and 12 months, bone density was stable among patients who received zoledronic acid, but there were significant declines in spine and hip BMD among women in the placebo group. Side effects weren't significantly different between the two groups.

The findings were published online Aug. 18 in the Journal of Clinical Oncology.

"Our study confirms that women experience significant bone loss due to cancer treatments and that zoledronic acid can prevent this loss," study lead author Dr. Dawn L. Hershman, assistant professor of medicine at Columbia University's College of Physicians and Surgeons, said in a university news release.

"While our findings are promising, it's too early for us to recommend this drug for all premenopausal women undergoing chemotherapy for breast cancer, because we don't yet have all the information we need on dosing, cost effectiveness, and whether this drug actually prevents bone fractures," Hershman said. "However, this research does show we need to be more vigilant about monitoring patients' bone densities before and during treatment, so we can protect bone health and offset bone fracture or osteoporosis risk."

Previous research found that similar drugs prevent bone loss in breast cancer patients during and after chemotherapy. Recent findings have suggested that zoledronic acid prevents bone loss in postmenopausal women and may reduce the risk of breast cancer recurrence.

SOURCE: American Society of Clinical Oncology, news release, Aug. 18, 2008