gms | German Medical Science

Bone metastases are common in patients with advanced cancer and may present major problems for physicians treating these patients. In addition to causing significant pain and hypercalcemia, bone metastases often result in fractures and debilitation. Treatment options for people with bone metastases depend on the primary cancer, metastases location and whether any bones are severely weakened or broken. Specific features of the cancer cells, general state of the patient and treatment history are other factors considered. Treatment approaches include local and systemic strategies. Chemotherapy, hormone treatment, immunotherapy, radiopharmaceuticals and bisphosphonates are causal systemic treatment options. Chemotherapy is used as the main treatment for metastatic cancers. The efficiency of chemotherapy in bone metastases is low, depending on the type of malignant cells. However, it may reduce significantly bone pain in patients with massive bone marrow infiltration. Hormone therapy is effective in the treatment of bone metastases of cancers presenting hormone receptors. In those patients hormone treatment reduces tumor burden and may initiate recalcification of bone. Immunotherapy is a systemic therapy using cytokines, monoclonal antibodies and tumor vaccines. The experience with these substances in bone is limited. Strontium-89, rhenium-186 and samarium-153 are radiopharmaceuticals, used to treat diffuse bone metastases. Their efficiency is moderate and depends on the type of metastases. The best results are achieved in osteoblastic metastases. Stimulation of osteoclast activity by factors secreted by tumor cells is believed be the primary mechanism of bone destruction. Bisphosphonates inhibit osteoclast-related bone resorption, and have become standard therapy in the treatment of hypercalcemia and bone complications in malignancy. These compounds, pyrophosphate analogs with a P-C-P backbone, which binds tightly to calcified bone matrix, include clodronate, pamidronate, ibandronate and zoledronate. All four are useful for the treatment of bone metastases, but zoledronate seems to be the most effective. Structural changes in bisphosphonates influence their relative potency as well as other potentially beneficial effects such as inhibition of tumor growth factors, alteration of adhesion molecules, and apoptosis of tumor cells. Bisphosphonates have been shown to decrease pain, skeletal fractures and other complications associated with bone metastases.