Review article
Bisphosphonates in the therapy of bone metastases from solid tumors
Tomislav Omrčen
; Center of Oncology and Radiotherapy, University Hospital Split, Split, Croatia
Abstract
Bisphosphonates (BPs) are drugs that prevent bone loss in the bones affected by malignant disease. Bone homeostasis is maintained by the activity of osteoblasts and osteoclasts. It is generally accepted that activation of osteoclasts is a key step in the emergence and development of bone metastases, and that bone resorption is important not only in classical lithic lesions but also in osteoblastic bone metastases. BPs inhibit osteoclast activity and stimulate osteoclast apoptosis. Thus, osteoclasts are a key therapeutic target in the treatment of bone metastases. Therefore, the use of BPs is a standard form of treatment and prevention of complications associated with bone metastases in patients with malignant tumors, regardless of the primary.
The greatest experience in the treatment of bone metastases from breast cancer is by intravenous BPs such as zolendronic acid, pamidronate and ibandronat. All of them show clinical activity. Until recently, randomized, placebo-controlled studies with BPs did not show a significant reduction in skeletal complications of bone metastases of prostate cancer. However, in the treatment of advanced hormone-resistant prostate cancer, zolendronic acid showed a reduction in the overall risk of skeletal complications by 36% and reduced the intensity of pain. The use of BPs in the treatment of bone metastases of other solid tumors has not been confirmed by randomized placebo-controlled studies. One study has shown a reduction in the incidence of bone metastases and their complications by about 30%. Patients with other tumors and symptomatic bone metastases may also be candidates for treatment with zolendronic acid, especially if bone metastases are a dominant site of metastasis and, if the expected survival is longer than 6 months. Patients with bone metastases of kidney cancer have a special benefit from BP therapy. Despite the apparent clinical benefit from the use of BPs, it is clear that they only play a part in preventing bone metastases and their complications, and some patients in spite of bone metastases never develop complications. Nowadays, one cannot predict which patients will benefit from BPs. Criteria are needed to define when BPs should be started and when they should be stopped. Before the administration of BPs, a primary disease, the extent of bone disease, expected survival, the probability that a patient would experience complications related to bone metastases should be taken into consideration.
Keywords
bone metastases; bisphosphonates
Hrčak ID:
278785
URI
Publication date:
30.11.2009.
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