Bisphosphonates - the "Bone Strengtheners"
When breast cancer cells settle in the bone they can stimulate the activity of natural cells that remodel bone called osteoclasts. These cells can over-absorb bone, making it weak and prone to fracture. Their activity can also cause bone pain, and sometimes lead to dangerous elevation of blood calcium. The activity of osteoclasts can be dampened down by the use of one of the drugs called bisphosphonates. They significantly reduce the risk of fractures and the requirement for pain killers. They do not kill cancer cells.
There are many bisphosphonates available on the PBS for patients with bone metastases from breast or prostate cancer. These include Zometa, Pamidronate, Bonefos and XGeva.
Zoledronic Acid ("Zometa") is given by intravenous infusion in the chemotherapy suite either once a month, once every six weeks or once every three months. Zometa has the advantage of only taking 15 mins to infuse.
Bonefos is an oral preparation taken as two large 800 mg tablets on an empty stomach. It is probably not quite as effective as the intravenous bisphosphonates.
Denosumab ("XGeva") inhibits a molecule called RANK ligand which is the main regulator of osteoclasts and is produced by cancer cells. The drug stops osteoclasts from eating away at bone and has been shown to be slightly superior to the bisphosphonates at preventing fractures and pain in patients with bone metastases from breast cancer. It is given monthly via subcutaneous injection by your GP.
Bonefos and Xgeva are also used in different doses for treating osteoporosis.
Side-effects of Zometa and XGeva
There are many bisphosphonates available on the PBS for patients with bone metastases from breast or prostate cancer. These include Zometa, Pamidronate, Bonefos and XGeva.
Zoledronic Acid ("Zometa") is given by intravenous infusion in the chemotherapy suite either once a month, once every six weeks or once every three months. Zometa has the advantage of only taking 15 mins to infuse.
Bonefos is an oral preparation taken as two large 800 mg tablets on an empty stomach. It is probably not quite as effective as the intravenous bisphosphonates.
Denosumab ("XGeva") inhibits a molecule called RANK ligand which is the main regulator of osteoclasts and is produced by cancer cells. The drug stops osteoclasts from eating away at bone and has been shown to be slightly superior to the bisphosphonates at preventing fractures and pain in patients with bone metastases from breast cancer. It is given monthly via subcutaneous injection by your GP.
Bonefos and Xgeva are also used in different doses for treating osteoporosis.
Side-effects of Zometa and XGeva
- Fever: Usually within the first 24 hours. Paracetamol should be used, 2 x 500mg every 4 hours until the symptoms subside
- Aches and pains (myalgia): Usually within the first 24 hours. Paracetamol should be used, 2 x 500mg every 4 hours until the symptoms subside (maximum 8 tablets in a day).
- Allergic reaction (uncommon)
- Worsening of kidney function: we monitor this carefully, checking your calcium and kidney function before each dose
- Nausea (rare)
- Osteonecrosis of the jaw (rare). There is a serious risk that major dental work performed whilst you are on a course of Zometa or Xgeva may result in a rare condition called Osteonecrosis of the jaw. This is a serious destructive disorder of the jaw bone and it is difficult to treat. It is more common if Zometa or Xgeva have been used for longer periods of time (eg. > 12 months). It may rarely occur in patients even without the aggravating factor of dental procedures. The symptoms can vary but can include dull heaviness of the jaw or loosening of teeth. The condition may be worsened by concurrent radiotherapy to the jaw, and possibly by corticosteroids (prednisone) or chemotherapy drugs. Patients receiving Zometa or Xgeva should seek medical advice from myself or my nurse before having any major dental work performed, particularly extractions, crown and bridge and root canal therapy. Patients receiving bisphosphonates should seek immediate medical and dental advice for any dental pain or loose teeth. You should tell your dentist is you are on a bisphosphonate, and it is good practice whilst on these drugs to have a thorough dental check twice yearly.
Use of Bisphosphonates in Early Breast Cancer
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