A study found that Zometa (chemical name: zoledronic acid) didn't destroy or slow the growth of breast cancer cells when it was given before surgery to postmenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer. These results were reported at the 2009 San Antonio Breast Cancer Symposium.
Zometa is a medicine used to strengthen bones in women diagnosed with breast cancer that has spread to the bone. Zometa is given intravenously and can reduce bone pain and the risk of fractures. Zometa is a bisphosphonate. Bisphosphonates are most commonly used to strengthen bones and to treat osteoporosis in postmenopausal women who haven't been diagnosed with cancer, but are sometimes used to strengthen bones in women diagnosed with breast cancer.
Besides improving bone health, other research has shown that Zometa can:
- shrink breast cancer
- improve breast cancer's response to treatment
- reduce the risk of the cancer coming back or spreading
Based on these results, researchers wanted to know if treatment with Zometa before breast cancer surgery would kill breast cancer cells or slow the cancer's growth. Doctors call treatment given before surgery neoadjuvant therapy.
In this study, 110 postmenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer got one of three treatments before surgery:
- Zometa injection and 14 days of the aromatase inhibitor Femara (chemical name: letrozole), a hormonal therapy
- Femara alone
- placebo (sugar pill)
After the cancer tumors were removed, the researchers looked at the cancer cells for any signs that the cells were dying (called apoptosis) or weakened from the treatment given before surgery. Cell weakening was measured by tests called Ki67, progesterone receptor expression, and cell turnover index score.
The researchers compared cancer cells from women who got Zometa plus Femara or Femara alone before surgery to cells from women who got the placebo to see if the neoadjuvant treatments made a difference.
- Neither of the treatments increased cancer cell death.
- Femara -- alone or with Zometa -- did seem to weaken the cancer cells, but there was no evidence that Zometa added to the benefits from Femara alone.
This study looked at breast cancer cells in the lab to see if Zometa was killing them or slowing their grow. Even though the study didn't seem to show any benefits from Zometa, it could be that Zometa has effects on other mechanisms in the cells that weren't measured in this study and are more positive. More research is needed to look at this possibility.
The results of studies like this -- even if they don't show a benefit -- help doctors better understand the behavior of breast cancer and give us hope for better ways to treat breast cancer. Stay tuned to Breastcancer.org for the latest news on breast cancer research that can make a difference, today or tomorrow.