Onkológia 3/2007

CONTEMPORARY POSSIBILITY OF THE TREATMENT OF BONE METASTASES

Consequences of bone metastases (pain, dysfunction, pathological fractures, spine instability, spinal cord compression) significantly decrease the quality of life of cancer patients. Both osteolytic and osteoblastic bone metastasis can be viewed as part of the spectrum of dysregulation of bone remodeling, i.e. the balance of osteoclast and osteoblast activity. The osteoclasts are probably responsible for bone resorption. The most potent, dominant and essential mediator of differentiation, activation and survival of osteoclasts is their binding to the so-called receptor activator of nuclear factor κB (RANK) ligand (RANKL) present on the surface of osteoblasts and stromal cells. Radiologic evaluation of skeletal metastases is reviewed. Stress is put to bone scan using Tc99m phosphate compounds in spite of its high (50 %) false positivity. In evaluation of treatment response is necessary to take into consideration the so-called „flare phenomenon“. In diagnosis of bone metastases and mainly in the monitoring of treatment response markers of bone resorption (peptides bound to colagens type I, C-terminal telopeptide ICTP) and markers of bone production - procolagens type 1 are described; in chosen specificity (90 %), the sensitivity is 50 %. Separately are analysed treatment options, i.e. external-beam radiation therapz (macrofractionation), systemic radionuclide therapy (32P, 89Sr, 153Sm), medical treatment (bisphosphonates) and surgical interventions.

Keywords: bone metastases, pathological fractures, RANKL, methods of detection of bone metastases, „flare phenomenon“; markers of bone resorption and of bone production; radiation therapy, bisphosphonates, surgical interventions.