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.

Consolidation of first-line therapy with busulphan and melphalan, and autologous stem cell rescue in children with Ewing's sarcoma.

According to the published report on current practice of hematopoietic SCT in Europe, high-dose therapy (HDT) with autologous stem cell support is a standard of care in paediatric patients with high risk (HR) or relapsed Ewing's sarcoma (ES). Randomized trials, however, have not confirmed the value of this procedure yet. In this retrospective analysis we intended to evaluate the role of HDT as a consolidation therapy in first remission of ES. A total of 102 patients were included in the analysis and divided according to the following risk factors: metastatic disease at presentation, feasibility of surgery and histological response after induction. Forty-one patients were classified as standard risk (SR) patients, while the remaining 61 children, with at least one risk factor, were classified as HR patients. HR group patients were non-randomized and qualified according to the decision of the local clinician to give a conventional consolidation (CC) or to perform high-dose chemotherapy and radiotherapy in selected patients. Twenty-six children were given CC while 35 patients were treated with HDT. The HDT consisted of oral BU 4 mg/kg p.o. in divided doses daily for 4 days (total dose 16 mg/kg) followed by melphalan 140 mg/m(2) i.v. on day -2. Probability of relapse-free survival (RFS) in median observation time was significantly worse in HR patients who were given CC therapy as compared with children with HR features receiving high-dose chemotherapy (0.27 vs 0.66 (P = 0.008); OS 0.31 vs 0.71 (P = 0.007), respectively). Patients from the SR group had a probability of RFS of 0.72 and OS of 0.75, and the difference between SR and HR patients after HDT was NS (P = 0.37). Our observation confirms that the consolidation of the first-line treatment with BU and melphalan improves the outcome in ES patients with HR features.

Brain Metastases from Ewing's Sarcoma. A Report of Two Cases and Review of the Literature.

Ewing's sarcoma accounts for approximately 30% of primary malignant bone tumors, mainly in children and young adults. At the time of diagnosis many patients already have metastatic spread of the disease, most often to the lungs and skeletal system. Intracerebral metastases are rare - the reported incidence is up to 4.3%. We describe two cases of metastatic deposits within the brain tissue. Signal intensity of the lesions was similar to that of meningioma on all sequences. Strong homogenous enhancement after gadolinium administration was also similar to meningioma.