Background. Ewing sarcoma (EWS) is a second most common pediatric bone tumor. About one quarter of all patients belong to a high-risk group characterized by a poor prognosis. In spite of high-dose chemotherapy (HDCT) with autologous hemopoietic stem cell transplantation (auto-HSCT) being traditionally viewed as a possible option for high-risk patients, there is stills no consensus on indications for this method in EWS patients.Study objective: to evaluate the HDCT effectiveness and most important prognostic factors in a prospective cohort of high-risk EWS patients. Materials and methods. A total of 73 EWS patients receiving treatment in R.M. Gorbacheva Memorial Institute were included in the study. All patients were characterized by one or several high-risk features: local (primary tumor volume >200 ml, axial localization, poor response to chemotherapy; n = 55; 76 %), primary disseminated disease (n = 58; 80 %), first chemoresponsive relapse (n = 7; 9 %). All patients received a myeloablative consolidation regimen consisting of busulfan 16mg/kg and melphalan 140mg/m2. In patients with primary disseminated disease an additional evaluation according to risk scale by R. Ladenstein et al. was performed. Based on risk points all patients were stratified as standard (n = 20), high (n = 26), and ultrahigh risk (n = 12).Results. The 5-year overall and event-free survivalfor a whole studied cohort were 40 and 37 %, accordingly. In patients with high-risk localized disease the 5-year overall and event-free survival were 48 and 45 %, accordingly. The HDCT regimen was characterized by acceptable toxicity. The main non-hematologic toxicities were infectious complications (n = 61) and gastrointestinal tract mucositis (n = 31). One patient of 76 died due to treatment-related complications. The multivariate analysis revealed the following risk factors: therapy response (hazard ratio (HR) 2.2; p <0.01), bone marrow involvement (HR 5.0; p = 0.01), primary tumor volume (HR 1.9; p = 0.01), and number of bone metastases (HR 2.2; p = 0.05). The risk group determined by R. Ladenstein score was also a good predictor for outcome with only 8 % of ultrahigh risk patients surviving 5 years past auto-HSCT.Conclusion. HDCT with auto-HSCT may potentially improve treatment results in some high-risk patient subgroups. While risk scale may help to determine patients most likely to benefit from this approach, the outcome in ultrahigh risk patients are still dismal.

Background. Ewing sarcoma (EWS) is a second most common pediatric bone tumor. About one quarter of all patients belong to a high-risk group characterized by a poor prognosis. In spite of high-dose chemotherapy (HDCT) with autologous hemopoietic stem cell transplantation (auto-HSCT) being traditionally viewed as a possible option for high-risk patients, there is stills no consensus on indications for this method in EWS patients. Study objective: to evaluate the HDCT effectiveness and most important prognostic factors in a prospective cohort of high-risk EWS patients. Materials and methods. A total of 73 EWS patients receiving treatment in R.M. Gorbacheva Memorial Institute were included in the study. All patients were characterized by one or several high-risk features: local (primary tumor volume >200 ml, axial localization, poor response to chemotherapy; n = 55; 76 %), primary disseminated disease (n = 58; 80 %), first chemoresponsive relapse (n = 7; 9 %). All patients received a myeloablative consolidation regimen consisting of busulfan 16mg/kg and melphalan 140mg/m 2 . In patients with primary disseminated disease an additional evaluation according to risk scale by R. Ladenstein et al. was performed. Based on risk points all patients were stratified as standard (n = 20), high (n = 26), and ultrahigh risk (n = 12). Results. The 5-year overall and event-free survivalfor a whole studied cohort were 40 and 37 %, accordingly. In patients with high-risk localized disease the 5-year overall and event-free survival were 48 and 45 %, accordingly. The HDCT regimen was characterized by acceptable toxicity. The main non-hematologic toxicities were infectious complications (n = 61) and gastrointestinal tract mucositis (n = 31). One patient of 76 died due to treatment-related complications. The multivariate analysis revealed the following risk factors: therapy response (hazard ratio (HR) 2.2; p <0.01), bone marrow involvement (HR 5.0; p = 0.01), primary tumor volume (HR 1.9; p = 0.01), and number of bone metastases (HR 2.2; p = 0.05). The risk group determined by R. Ladenstein score was also a good predictor for outcome with only 8 % of ultrahigh risk patients surviving 5 years past auto-HSCT. Conclusion. HDCT with auto-HSCT may potentially improve treatment results in some high-risk patient subgroups. While risk scale may help to determine patients most likely to benefit from this approach, the outcome in ultrahigh risk patients are still dismal.

Introduction.Neuroblastoma (NB) is the most common extracranial pediatric solid tumor. The high-risk group patients are characterized by adverse prognosis and require intensive complex therapy including high-dose chemotherapy (HDCT) with hematopoietic stem cell transplantation (auto-HSCT). The current study presents a single center experience of HSCT with auto-HSCT for high-risk NB performed in Raisa Gorbacheva Memorial Research Institute of Children Oncology, Hematology and Transplantation, First Pavlov State Medical University of St. Petersburg, Ministry of Health of Russia.Patients and methods.A cohort of 72 consecutive high-risk NB patients was included in the study. Among them 69 patients received Bu-Mel conditioning regimen (busulfan 16 mg/kg, melphalan 140 mg/m2 ), in 3 patients the 5D/5D regimen was used (carboplatin 1000 mg/m2 , irinotecan 150 mg/m2 , temozolomide 750 mg/m2 , etoposide 400 mg/m2 , cyclophosphamide 140 mg/kg). In most cases the autologous hematopoietic stem cells source was bone marrow (BM) (n = 59; 82 %), peripheral blood stem cells (PBSC) (n = 11; 15 %), or BM and PBSC (n = 2; 3 %). In 52/66 (79 %) patients with initial bone marrow involvement the potential transplant contamination was assessed by flow cytometry.Results.The 2-year and 5-year overall (OS) and event-free (EFS) survival was 61 % and 48 %, 41 % and 35 % accordingly. The main adverse factors for OS and EFS were age of more than 18 months at diagnosis, combined bone marrow and bones involvement, MYCN amplification, initial neuron-specific enolase level of more than 100 ng/ml, primary resistance or relapse, and metaiodobenzylguanidinepositive lesions persistence prior to or after HSCT with auto-HSCT.Conclusions.The results achieved are comparable to those described for similar cohorts. Some patient subgroups are unlikely to achieve response after HSCT with auto-HSCT. Therefore, additional stratification methods and treatment modalities are needed.Conflict of interest. The authors declare no conflict of interest.Funding. The study was performed without external funding.

A total of 40 patients (median age 6 years, range 1-28 years) with high-risk malignant brain tumors received a single (n = 35) or tandem (n = 5) high-dose chemotherapy (HDCT) with autologous hemopoietic stem cell transplantation (auto-HSCT). The 2-year OS and DFS are 52% and 47%, accordingly, with median follow-up of 24 (range 2-96) months. The patients without complete response at the time of auto-HSCT had worst prognosis with 53% DFS in patients with partial remission and 25% in patients with disease stabilization (p = 0.001). Patients with relapsed tumor had worse prognosis, than high-risk patients in the first remission with DFS 26% and 62%, accordingly (p=0.02). The relapse rate also correlated with patient's age (38% DFS in patients younger, than 4 years and 60% in older patients, p = 0.005) and tumor morphology (63% DFS in patients with medulloblastoma, 60% in patients with germ-cell tumors, 45% in other embryonal CNS tumors, p = 0.05). The 4th-grade transplant-related toxicity and mortality rates were observed in 13% and 18% of patients, accordingly. Therefore, HDCT with auto-HSCT in young patients with high-risk CNS tumors is characterized by acceptable toxicity and allows improving overall therapy results.

The combined treatment results of 122 pediatric (5–17 years) osteosarcoma patients receiving therapy in N.N.Petrov Oncology Research Institute in 1980–2010 were analyzed. Among the patients, 72,6% had localized form and 27,4% had metastatic disease. The median follow-up was 63,2 (13–378) months. Treatment results correlated with process dissemination, chemotherapy regimen and surgical procedure used. The best results were achieved in patients receiving organ-sparing surgery, which can be performed in, approximately, 80% of the patients.