Researchers in a new study said that a drug that helps strengthen bones may also fight breast cancer. The findings were presented Thursday at the CTRC-AACR San Antonio Breast Cancer Symposium in Texas and said that women who were given the drug Zometa, as part of their initial treatment had greater tumor shrinkage and were less likely to need radical surgery. The drug zoledronic acid (Zometa) is given to prevent bone loss caused by certain cancer treatments was found to also greatly cut the risk that cancer would recur in women who developed the disease before menopause.

Zometa is already an approved drug to treat breast cancer that has spread to the bone and was reported to lower the risk of breast cancer recurrence in pre-menopausal women with early estrogen- or progesterone-positive tumors. A second ongoing study is testing Zometa in 3360 women who had breast cancer before menopause and in a mini report said that 205 participants had chemotherapy in order to try to shrink their tumors before surgery. The researchers reported that the women who were given infusions of Zometa along with the chemotherapy had a third more tumor shrinkage and therefore were likely to need the lump removed rather than the whole breast.

Study leader Dr. Robert Coleman a professor of medical oncology at the University of Sheffield in England said 11 % of the women who took Zometa had a complete response to the treatment with no evidence of cancer in their breasts or lymph nodes as compared to 6 % of the women who were only given chemotherapy. The researchers also reported that the residual invasive tumor size was 42.4 millimeters in the chemotherapy alone group, and 28.2 millimeters in the combination group.

"This data suggests that zoledronic acid is doing something more than protecting bone," said Dr. Coleman. "It's not practice-changing. It's hypothesis-generating, which will lead to the design of new trials to look at this in detail. But this is the first patient-related evidence."

Dr. Eric Winer of the Dana-Farber Cancer Center in Boston and a spokesman for the American Society of Clinical Oncology, the largest group of doctors who treat cancer said partial studies like this do not warrant changing a practice but as these results are surprising they deserve more testing. He added that such significant benefits from the bone drug before surgery "is not something I would have expected." The study was sponsored by Zometa's maker, Swiss-based Novartis AG, while the study leader consults for the company.

At the conference reports that newer hormone-blockers called aromatase inhibitors, or AIs, do a better job of preventing cancer recurrences and may give a slight survival advantage over the long-used drug tamoxifen were doing the rounds. "At this point in time, there is a slight increase in survival in patients treated with AIs but it is not statistically significant," said that study's leader, Dr. James Ingle of the Mayo Clinic in Rochester, Minn.

Stephen Johnston, a consultant in medical oncology and reader in breast cancer medicine at Royal Marsden Hospital and Foundation in the United Kingdom said, "The combination shows benefits in controlling the disease and controlling it for longer than using endocrine therapy alone. The suggestion is that combined therapy may be the best approach."

The San Antonio Breast Cancer symposium is sponsored by the American Association for Cancer Research, Baylor and the University of Texas Health Science Center at San Antonio.