Bisphosphonates are medicines used to prevent or treat osteoporosis. Some research has suggested that bisphosphonates also might help stop breast cancer from spreading to the bones by making it harder for breast cancer cells to grow in bones and might help reduce the risk of the cancer coming back (recurrence) in women diagnosed with early-stage breast cancer.
A new study has found that the bisphosphonate Boniva (chemical name: ibandronate) doesn’t reduce the risk of recurrence in women diagnosed with early-stage breast cancer with a high risk of recurrence.
The research was published online on Aug. 26, 2013 by the Journal of Clinical Oncology. Read the abstract of “German Adjuvant Intergroup Node-Positive Study: A Phase III Trial to Compare Oral Ibandronate Versus Observation in Patients With High-Risk Early Breast Cancer.”
Boniva can be given intravenously, but in this study it was in the form of a pill taken by mouth.
The GAIN (German Adjuvant Intergroup Node-Positive) study randomly assigned about 3,000 women diagnosed with early-stage, node-positive breast cancer with a high risk of recurrence to receive one of two dose-dense chemotherapy regimens. Dose-dense chemotherapy means that the chemotherapy medicines are given every 2 weeks, instead of the standard schedule of every 3 weeks.
About half the women had fewer than five positive lymph nodes and about half had more than five positive lymph nodes.
After they completed chemotherapy, two-thirds of the women were randomly assigned to get Boniva for 2 years. The rest of the women were monitored for 2 years.
There was no difference in disease-free survival (how long the women lived without the cancer coming back) between women who got Boniva and women who didn’t get Boniva. This means there was no difference in the risk of breast cancer recurrence between the two groups.
There also was no difference in overall survival (how long the women lived whether or not the cancer came back) between the two groups.
Although this study suggests that oral Boniva doesn’t reduce breast cancer recurrence risk, it may still make sense for postmenopausal women to strengthen bones that may be weakened by some breast cancer treatments.
If you’re a postmenopausal woman who’s been diagnosed with breast cancer or osteoporosis, your doctor may recommend a bisphosphonate such as Boniva to strengthen your bones. 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.
For more information on keeping your bones strong, visit the Breastcancer.org Bone Health section.