[Effects of oncological therapy on bone disorders].

Due to increasing incidence of cancer disease and the searching for new, aggressive methods of therapy, more attention is focusing on applied treatment consequences. The specificity of oncological drugs allows to destroy cancer cells, simultaneously destroying and disrupting the functioning of healthy tissues. Side effects concern infertility, urolotoxicity, nephrotoxicity, neurotoxicity or bone marrow suppression. Chemotherapy can also be affected on physiological function of movement system and the skeleton construction. Mineral status disorders and skeletal changes lead to secondary forms of osteopenia and osteoporosis and refer oncological patients of any age. The main cause of these conditions is an imbalance between osteoclast and osteoblast activity, occurring as a result of drug interactions, parathyroid hormone-like proteins or interleukins. In addition to the direct effect on bone tissue, disorders in its construction and metabolism are also manifested as a consequence of hypogonadism. The sexual hormones at normal level can inhibit process of bone destruction, increase parathormone level, stimulate active vitamin D3 formation and intestinal calcium absorption. The deficiency of estrogens and androgens indirectly leads to disorder of bone metabolism and homeostasis. Symptoms such as musculoskeletal pain and fractures appear in the late stage of degeneration. Moreover, the appropriate selection of therapy and dosage, compatible with the patient's age and condition are crucial for treatment. Early bone loss should be prevented by supplementing with calcium, vitamin D3, hormone replacement therapy or bisphosphonates. The physical activity and proper diet are important as well. The aim of the study was to characterize the most common oncological treatment regimens, considering the long-term side effect of applied therapy and its influence on the skeletal mineralization and trace element profile. Based on the mechanism of drug action, the disorders observed after pharmacotherapy were described. The processes leading to bone's composition changes were discussed and prevention of their occurrence were estimated.