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A review of 30 studies finds that a class of drugs called bisphosphonates is beneficial
in breast cancer patients whose cancer has spread to the bone. Bone is one of the most
common sites to which breast cancer can metastasize, or spread. The study finds that
bisphosponates can reduce complications in breast cancer patients whose cancer has
affected the bone. Therefore, the researchers conclude that these drugs should be
considered as soon as breast cancer has spread to the bone to maximize the benefit of
treatment.
When breast cancer spreads past the breast and axillary (armpit) lymph nodes, it often
spreads first to the bone. These breast cancer tumors in the bone are called "bone
metastases." As advanced breast cancer dissolves portions of bone, a variety of
problems can occur. Bone metastases can cause pain, decreased activity, and potentially
severe problems such as fractures. Other complications that can arise from bone metastases
include the surgical treatment for fractures, hypercalcemia (abnormally high levels of
calcium), and spinal cord compression (vertebral damage due to pressure on the spinal
cord).
A group of drugs called bisphosphonates are currently used to help treat osteoporosis,
a degenerative bone disease affecting mainly post-menopausal women. In patients with
osteoporosis, the bone loses a significant portion of its density, greatly increasing the
risk of serious fractures. One bisphosphonate, Aredia (genetic name, pamidronate
disodium), has already been approved by the U.S. Food and Drug Administration (FDA) to
help treat bone metastases caused by breast cancer while a number of other bisphosphonates
are currently under investigation for this use.
Aredia is administered intravenously (through a vein) along with other cancer
treatments, such as chemotherapy. Clinical studies have shown that breast cancer patients
with bone metastases who are given Aredia tend to experience a delay in or reduction of
bone pain, fractures, and other bone complications compared to patients who do not receive
Aredia. Possible side effects of Aredia include fever, fatigue, nausea and vomiting,
initial bone pain, lack of appetite, and anemia (decrease in red blood cells).
In the current study, Joy Ross, a research fellow at the Royal Marsden Hospital in
London, England, and colleagues reviewed 30 published reports on bisphosphonate use in
breast cancer patients whose cancer had spread to the bone. In the reports, patients
treated with bisphosphonates were compared to others who were treated with another
bisphosphonate, a placebo (or inactive pill), or standard care.
The results of their analysis showed that women who were treated with bisphosphonates
had fewer skeletal complications from breast cancer compared to women who did not receive
bisphosphonates. Therefore, the researchers conclude that bisphosphonates should be given
to breast cancer patients whose cancer has spread to the bone. According to Ross and
colleagues, treatment should continue until no longer needed. Previous studies reveal that
further research is needed before all types of bisphosphonates can be recommended for use
in breast cancer patients.
Types of bisphosphonates under investigation for treating bone metastases include:
- Didronel (generic name, etidronate)
- Bonefos, Clostoban, Loron, Ostac (generic name, clodronate)
- Skelid (generic name, tiludronate)
- Fosamax (generic name, alendronate)
- Zometa (generic name, zoledronate)
Additional Resources and References
- The report, "Systematic Review of Role of Bisphosphonates on Skeletal Morbidity in
Metastatic Cancer," is published in the August 30, 2003 issue of the British Medical
Journal, http://bmj.com/
- To learn more about advanced (metastatic breast cancer), including bone metastases,
please visit http://www.imaginis.com/breasthealth/metastatic.asp
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