Zoledronic Acid May Prevent Cancer Return in Postmenopausal Women With Early-Stage Breast Cancer
Researchers with the AZURE trial found that giving the bone strengthening medicine zoledronic acid (Zometa) after standard treatment for early-stage breast cancer lessened the chance of cancer returning in postmenopausal women. It also lessened the chance of bone problems in all women.
Background and Goals
Bisphosphonates, such as zoledronic acid, can help prevent bone loss. They are often given to women with breast cancer that spread to the bones and to postmenopausal women who are taking aromatase inhibitors, breast cancer medicines that can damage the bones.
Researchers with the AZURE trial wanted to learn if giving zoledronic acid along with standard treatment during early-stage breast cancer could not only help with bone problems, but also prevent a recurrence, or return of cancer.
Early results of AZURE, reported in 2010, suggested zoledronic acid had little effect on recurrence. These final results report follow-up data from a median of 7 years after treatment ended.
The phase III study looked at disease-free survival, DFS, the time between start of treatment and breast cancer recurrence or death. They later added a similar factor called invasive disease-free survival, IDFS, because the accepted definition of DFS changed during the time of the study. The team also collected data on menopausal status and bone health.
The researchers randomly assigned 3,360 women with stage II or III breast cancer who had already had surgery to
- Standard treatment alone, or
- Standard treatment and 5 years of treatment with zoledronic acid, given by vein every 3 to 4 weeks for six doses, then every 3 months for eight doses, then every 6 months for five doses
After treatment ended, researchers checked up on participants every year.
DFS was not different enough between the two groups to be statistically significant, or likely caused by more than chance. Recurrence or death within 5 years happened to
- 30 percent of women in the standard treatment group
- 28 percent of women in the zoledronic acid group
Hormonal status, whether the cancer grows because of estrogen or progesterone, didn’t seem to make a difference in DFS.
Postmenopausal women benefited from the treatment though – invasive disease-free survival (IDFS) was significantly better in women who were at least 5 years past menopause. Recurrence or death within 5 years happened to
- 35 percent of post-menopausal women in the standard treatment group
- 28.5 percent of post-menopausal women in the zoledronic acid group
There were bone health benefits for women who took the study medicine. Bone fractures were seen in
- 8.3 percent of the standard treatment group
- 6.2 percent of the zoledronic acid group
Breast cancer was also less likely to spread to the bones in the zoledronic acid group.
Because of the effect zoledronic acid had on recurrence in postmenopausal women, the researchers suggest doctors consider adding the medicine to standard treatment for women with early-stage breast cancer who are at least 5 years past menopause.
What This Means for You
Bone health is important to keep in mind during breast cancer treatment. If you’re post-menopausal, you may be happy to see that there is a medicine that could make your bones stronger and make breast cancer return less likely.
To learn more about taking care of your bones, read our Guide to Understanding Bone Health.
The researchers didn’t see enough benefit to suggest prescribing zoledronic acid to premenopausal women. However, many other medicines are being tested in the early-stage setting. If you are interested in taking part in a clinical trial, visit ClinicalTrials.gov and talk to your doctor.
Coleman, Robert; Cameron, David; Dodwell, David. Adjuvant zoledronic acid in patients with early breast cancer: final efficacy analysis of the AZURE (BIG 01/04) randomised open-label phase 3 trial. The Lancet Oncology. Volume 15, issue 9, pages 997-1006, August 2014; doi: 10.1016/S1470-2045(14)70302-X.