Zometa (chemical name: zoledronic acid) is a bisphosphonate, a type of bone strengthening medicine. Right now, Zometa is used to strengthen bones and lower the risk of breaking a bone or other bone complications in women diagnosed with metastatic breast cancer that has spread to the bones.
Some studies have suggested that Zometa also might help stop breast cancer from spreading to bone by making it harder for breast cancer cells to grow in bones. This could help reduce the risk of the cancer coming back (recurrence).
Results from the ongoing ABCSG-12 study (the Austrian Breast Cancer Study Group 12) found that Zometa and hormonal therapy after surgery could reduce the risk of the cancer coming back in premenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer compared to only hormonal therapy treatment. The research was published in The Lancet Oncology and presented at the 2011 annual meeting of the American Society of Clinical Oncology (ASCO).
After surgery and other treatments (radiation therapy, chemotherapy, hormonal therapy) for early-stage breast cancer, premenopausal women diagnosed with hormone-receptor-positive cancer often will be treated with 5 or more years of hormonal therapy to reduce the risk of the cancer coming back. Treatments given after surgery and primary treatments are called adjuvant treatments, so hormonal therapy given after surgery is called adjuvant hormonal therapy. Premenopausal women usually take tamoxifen as adjuvant hormonal therapy. Either tamoxifen or an aromatase inhibitor is given as adjuvant hormonal therapy in postmenopausal women.
The aromatase inhibitors are:
- Arimidex (chemical name: anastrozole)
- Aromasin (chemical name: exemestane)
- Femara (chemical name: letrozole)
In the ABCSG-12 study, 1,808 premenopausal women diagnosed with stage I or II hormone-receptor-positive breast cancer had surgery and then hormonal therapy to reduce the risk of the cancer coming back. The women took either tamoxifen (brand name: Nolvadex) or Arimidex for the hormonal therapy medicine. Half the women also got Zometa along with the hormonal therapy medicine.
About 5 years after surgery, the women who got Zometa and hormonal therapy had 32% better disease-free survival compared to the women who got only hormonal therapy. Disease-free survival is being alive without the cancer coming back. Better disease-free survival means the women who got Zometa and hormonal therapy had fewer breast cancer recurrences.
Overall survival -- the time a woman lived whether or not the cancer came back -- was 33% better in women who got Zometa and hormonal therapy. This difference wasn't statistically significant though, which means that it could have been due to chance and not because of the difference in treatments.
These results suggest that Zometa (and possibly other bisphosphonates) may be useful, when given along with hormonal therapy, to reduce the risk of cancer coming back in premenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer. More research is needed before we know exactly how helpful Zometa is.
Other bisphosphonates include:
- Actonel (chemical name: risedronate)
- Boniva (chemical name: ibandronate)
- Fosamax (chemical name: alendronate)
- Reclast (chemical name: zoledronic acid -- the same active ingredient as Zometa)
Reclast is given intravenously once a year. The others are pills taken by mouth.
If you're a premenopausal woman and have been diagnosed with early-stage breast cancer, you may want to ask your doctor if a bisphosphonate makes sense for you. If you're prescribed a bisphosphonate, know that some of them need to be taken in a specific way and all may cause serious side effects; make sure you and your doctor talk about how to take the medicine.