Published: Mar. 28, 2007
Updated: Aug. 22, 2011
Solid tumor cancers, such as breast, prostate, lung and kidney cancers, often spread to other parts of the body.
The bones are a common site of spread for these cancers. Other cancers, such as multiple myeloma, may affect the bones directly.
When cancer spreads to the bones, it can result in pain and other suffering for the patient. Pain may limit movement.
The bones may become weak and break, limiting the patient’s functioning. Destruction of the bone can cause calcium to leak into the bloodstream, resulting in increased levels of calcium in the blood, a condition called hypercalcemia.
Mild symptoms hypercalcemia include sleepiness, loss of appetite, thirst and frequent urination, and constipation. More severe hypercalcemia symptoms include nausea and vomiting, confusion, and even coma.
The degree of symptoms relates more to how fast the calcium rises than to the actual level itself, although most patients with very high calcium levels will have symptoms.
Bone metastases may be treated with a variety of treatments, including radiation therapy, chemotherapy, and hormone therapy. A newer approach to treating bone metastases is with a group of drugs called bisphosphonates.
Bisphosphonates are drugs originally developed to fight osteoporosis. In patients with cancer that has spread to the bone, bisphosphonates can slow down or stop the bone destruction caused by cancer in the bones.
This prevents broken bones, bone pain and hypercalcemia, a condition in which calcium from destroyed bone leaks into the blood causing symptoms such as sleepiness, vomiting, and renal failure.
Perhaps even more promising, several cancer researchers also discovered in the 1990s that bisphosphonate treatments were also useful in preventing the spread of cancer metastases, causing metastatic tumors to shrink and perhaps even preventing bone metastases from occurring at all in breast cancer patients.
For many patients, bisphosphonates can reduce the need for radiotherapy and surgery, reduce pain, reduce or delay the onset of broken bones and improve quality of life.
Bisphosphonates can be used for any type of cancer in which bone destruction is involved. In particular, bisphosphonates have been used to treat bone metastases in patients with breast cancer, lung, kidney and prostate cancers, as well as multiple myeloma.
Zometa® (zoledronic acid) and Aredia® (pamidronate) are two IV bisphosphonate drugs that are given to patients diagnosed with bone metastases. They both work equally well but are somewhat different in how they are given and their side effects.
Aredia (pamidronate) is approved for the treatment of hypercalcemia, the treatment of multiple myeloma, and the treatment of bone metastases from breast cancer. It is given intravenously (IV) once a month, over two to four hours.
Zometa (zoledronic acid) is approved for the treatment of hypercalcemia, the treatment of multiple myeloma, and the treatment of bone metastases from all solid tumors. Infusion of Zometa (zoledronic acid) takes 15 to 45 minutes and is administered to the patient about once every three to four weeks.
Side effects of both Zometa and Aredia, especially kidney toxicity, are related to the dose, the frequency, and the duration of the infusion. If kidney toxicity is a concern, the infusion time can be increased to the longer end of the range described above.
If a patient cannot receive IV bisphosphonates for some reason, they may benefit from an oral bisphosphonate.
Oral bisphosphonate drugs include:
Patients taking bisphosphonates may experience bone pain, fever, and bouts of conjunctivitis (pink eye).
Patients may also develop abnormally low levels of calcium in the blood, called hypocalcemia.
If you should start to feel nauseous or drowsy, inform your doctor so that he or she can monitor your calcium and phosphate levels.
If a bisphosphonate is prescribed for you, you will receive more information about any potential side effects with that specific drug.
This article is intended as a resource for patients receiving their cancer care at Duke University Hospital or Duke Clinic. It is not intended to substitute for medical advice from your health care team. If your doctor’s instructions differ from the information in this article, please talk with your doctor before making any changes.
Source: Cancer Patient Education Program, approved Duke Patient / Family Education Committee. 3/2005