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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