Response to chemotherapy estimates by FDG PET is an important prognostic factor in patients with Ewing sarcoma.

BACKGROUND: Response to chemotherapy is a prognostic factor in patients with Ewing sarcoma (ES); the role of FDG PET to predict response in these patients has not been thoroughly investigated. We evaluated the diagnostic accuracy and the potential of FDG PET to predict response to chemotherapy (CHT). MATERIALS AND METHODS: We analyzed data of 50 patients with ES (median age 12.6 years). All patients were treated with neoadjuvant CHT, and underwent surgery for local control. All patients had (18)F-FDG PET/CT at diagnosis and after induction CHT, prior to local control. We compared response assessed by histopathology with FDG PET using standard uptake values (SUVs). RESULTS: Median SUV at diagnosis (SUV I) was 5 (range 1.2-17), and median SUV after neoadjuvant chemotherapy (SUV II) was 1.8 (range 0-8.4). Median SUV II/I ratio was 0.3 (range 0-1). SUV at diagnosis was significantly lower in patients with good histological response than in patients with poor histological response (median 3.8 vs. 7.2, p 0.02). We found a significant correlation between SUV II and outcome; the positive predictive value of an SUV II ≤ 2.5 for favorable response was 84.21 %, and the median SUV II was significantly higher in patients with disease progression (2.3 vs. 1.6, p = 0.04). In multivariate analysis, necrosis and SUV II were significant predictors of outcome. CONCLUSIONS: (18)F-FDG PET demonstrates high diagnostic accuracy for response to initial chemotherapy in patients with ES and it correlates with outcome. The role of FDG PET in predicting response and outcome should be further investigated.

Decreased bone mineral density and alteration in biochemical bone metabolism markers in children affected by bone tumors after completion of therapy.

UNLABELLED: The aim of this study was to assess bone mineral density (BMD) and biochemical bone metabolism markers in patients with bone tumors after anti-cancer treatment. The study included 27 patients (median age 15 years) with malignant bone tumors and 27 healthy children. In all subjects, BMD and body composition were measured by dual-energy x-ray absorptiometry. Serum bone markers were determined by immunoenzymatic assays. After completion of treatment, patients with bone tumors had significantly decreased total and lumbar spine BMD. We observed lower calcium and vitamin D levels in patients and comparable values of bone turnover markers (carboxyterminal telopeptide of collagen type I - CTX, bone alkaline phosphatase - BALP and osteocalcin - OC) in both groups of children. However, the level of carboxylated osteocalcin (cOC) was significantly lower (p<0.01) and undercarboxylated OC (ucOC) was higher (p<0.05) in patients than in controls. Additionally, we observed similar values of anthropometric parameters in the subgroups of patients treated with methotrexate (MTX) or without MTX. In patients treated without MTX we found lower (p<0.05) ratio of cOC/ucOC, lower vitamin D level and higher CTX concentrations. Patients with bone tumors after anticancer treatment had decreased bone mineral density and alterations in bone metabolism markers with potential decrease in bone formation. KEYWORDS: bone cancer survivors, bone mineral density, bone formation markers, bone resorption markers, methotrexate.