Bisphosphonates
Reduce Skeletal Fractures in Patients with Bone Metastasis
According to a recent article published in BMJ, the use of
bisphosphonates reduces the incidence of skeletal fractures
in patients with bone metastasis.
As cancer becomes more advanced, it tends to spread throughout
the body, with the bones being a common site of spread for
many cancers. Spread of cancer to the bone from its original
site is referred to as bone metastases. Through complex biological
pathways, bone metastases severely reduce the quality of life
of a patient and may ultimately cause debilitating bone pain,
bone fractures, spinal compression (a life-threatening condition)
and/or abnormalities in calcium levels in the blood. Treatment
for bone metastases is aimed primarily at reducing pain, delaying
the time to fractures or reversing hypercalcemia (high levels
of calcium in the blood). Treatment may consist of radiation
therapy, bisphosphonates, hormone therapy and/or chemotherapy,
depending upon the type of cancer from which the metastasis
originated. Besides the physical sequelae that can be caused
by bone metastasis, such as bone fractures, the pain that
it can cause may literally force patients to become bedridden.
Researchers are evaluating ways in which to prevent or reduce
the pain or fractures caused by bone metastasis, not just
provide treatment once they occur.
Bisphosphonates are a class of drugs used to for the treatment
of cancer-related hypercalcemia (high levels of calcium in
the blood) and treatment of bone metastases in patients with
advanced cancers. Bisphosphonates decrease the rate of bone
destruction in patients with bone metastases and clinical
studies have demonstrated that bisphosphonates can significantly
decrease the pain and number of fractures occurring from bone
metastases. Research involving bisphosphonates is ongoing,
as physicians are trying to determine the optimal timing of
treatment with bisphosphonates in the course of cancer.
Recently, researchers analyzed data from 30 clinical trials
that had evaluated the use of bisphosphonates in various types
of cancers, mainly prostate, breast and multiple myeloma.
In each trial, patients with bone metastases from a specific
cancer received treatment with either a bisphosphonate, standard
care for their cancer, placebo (inactive substitute) or a
different bisphosphonate and were directly compared. Overall,
patients treated with a bisphosphonate had a delayed time
to skeletal fractures, a reduced need for radiation therapy
to treat bone metastasis, a reduction in hypercalcemia and
a reduction in the need for orthopedic surgery. Treatment
with bisphosphonates was well tolerated, and treatment was
safely continued for years. There was no impact on survival
between the groups of patients treated with or without bisphosphonates.
Intravenous aminobisphosphonates (Zometa ®, Aredia ®)
appeared to produce a greater benefit than oral bisphosphonates
(Didronel ®, Bonefos ®).
The researchers concluded that bisphosphonate use appears
to significantly reduce side effects caused by bone metastasis
in patients with advanced cancer, ultimately resulting in
an improvement in quality of life. The authors stated that
bisphosphonate use at the onset of diagnosis of bone metastasis
appears reasonable and may delay or prevent some problems,
such as bone fractures, associated with bone metastasis. Future
clinical trials evaluating duration of use and timing of bisphosphonates
are warranted. In addition, results from a clinical trial
evaluating bisphosphonate use in earlier stage cancers are
awaited to determine if early bisphosphonate use may help
prevent bone metastasis. Patients diagnosed with bone metastasis
may wish to speak with their physician about the risks and
benefits of bisphosphonates.
Reference: Ross JR, Saunders Y, Edmonds PM, et al. Systematic
Review of Role of Bisphosphonates on Skeletal Morbidity in
Metastatic Cancer. BMJ ( British Medical Journal). 2003;327:469-471.
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