When cancer spreads to bones, it can cause pain and lead to bones breaking (fractures) and other problems. Drugs like bisphosphonates and denosumab can lower the risk of these problems.
Bisphosphonates are drugs that can be used to help strengthen bones and reduce the risk of fractures and pain in bones that have been weakened by metastatic breast cancer. Examples include pamidronate (Aredia®) and zoledronic acid (Zometa®). They are given intravenously (IV).
Bisphosphonates may also help against bone thinning (osteoporosis) that can result from treatment with aromatase inhibitors or from early menopause as a side effect of chemotherapy. There are a number of medicines, including some oral forms of bisphosphonates, to treat loss of bone strength when it is not caused by cancer spread to the bones.
Bisphosphonates can have side effects, including flu-like symptoms and bone pain. They can also lead to kidney problems, so people with poor kidney function may not be able to be treated with these drugs.
A rare but very distressing side effect of bisphosphonates is osteonecrosis (damage) in the jaw bones or ONJ. It can be triggered by having a tooth removed while getting treated with a bisphosphonate. ONJ often appears as an open sore in the jaw that won't heal. It can lead to loss of teeth or infections of the jaw bone. Doctors don't know why this happens or how to treat it, other than to stop the bisphosphonates. Maintaining good oral hygiene by flossing, brushing, making sure that dentures fit properly, and having regular dental checkups may help prevent this. Most doctors recommend that you have a dental checkup and have any tooth or jaw problems treated before starting bisphosphonate treatment.
Denosumab (Xgeva®, Prolia®) is another drug that can help reduce the risk of problems from breast cancer metastasis to the bone. It works differently from bisphosphonates.
In studies of patients with breast cancer that had spread to the bone, it seemed to help prevent problems like fractures (breaks) better than zoledronic acid. It also can help bones even after bisphosphonates stop working.
In patients with cancer spread to bones, this drug is injected under the skin every 4 weeks. Side effects include low blood levels of calcium and phosphate, as well as ONJ This drug does not seem to affect the kidneys, so it is safe to take if you have kidney problems.
Denosumab can also be used to strengthen bones in breast cancer patients with weak bones who are being treated with aromatase inhibitors. When it is used for this purpose, it is given less often (usually every 6 months).
For more information about treating cancer spread to bones, see Bone Metastases.
Last Revised: 02/22/2016