Cancer and the use of a comprehensive anti-cancer treatment are unfavorable factors, which have a significant impact on bone mass accumulation, bone mineralization and consequently the occurrence of osteoporosis. Bone turnover is regulated by complex mechanisms, among which an important role play OPG/RANK/RANKL signaling pathway, adipokines, and fetuin-A. The aim of the study was to evaluate bone mineral density and concentrations of leptin and fetuin-A in patients with osteosarcoma after anti-cancer treatment.
Materials and methods: The study included 50 children and adolescents aged 10-21 years. The study group consisted of 25 patients with osteosarcoma and 25 healthy counterparts as a control group. The examination was conducted 2 months after the last course of postoperative chemotherapy and included densitometric measurements: bone mineral content (BMC), bone mineral density (BMD), fat mass, lean mass and biochemical measurements: serum concentrations of calcium, magnesium, phosphate, 25-hydroksyvitamin D, alkaline phosphatase, leptin and fetuin-A. Concentrations of leptin and fetuin-A were determined by immunoenzymatic methods.
Results: In patients with osteosarcoma after anti-cancer treatment, we observed significantly reduced bone mineral content, bone mineral density and lean body mass compared with the healthy children (p < 0.05, p < 0.01, p < 0.05, respectively). Mean values of z-score of the whole body BMD and z-score of the lumbar BMD L1-L4 were significantly lower in patients than in the controls (p < 0.001). The serum concentrations of phosphate, magnesium, and alkaline phosphatase in both studied groups were similar, while calcium was significantly lower (p < 0.05) in patients than in the healthy children. The concentration of 25-hydroxyvitamin D was about two-fold lower, while leptin approximately 2.5-fold higher in patients than in the controls. The mean value of fetuin-A was similar in both studied groups. Statistically significant positive correlations between body composition parameters and the values of BMD, as well as between anthropometric parameters and leptin and fetuin-A were observed.
Conclusion: The deficit in bone mass observed in patients with malignant bone tumors after anti-cancer treatment might be the result of decreased serum calcium and vitamin D concentrations. The observed correlation between anthropometric and biochemical parameters may indicate the link between bone and adipose tissue metabolism.