Treatment of Ewing Sarcoma, Paediatric Bone Sarcomas and Severe Paediatric Spinal Deformities in Finland

Background Ewing sarcomas are rare highly malignant tumours, mainly affecting the paediatric and adolescent population. The prognosis is dismal without therapy, but with modern chemotherapy and local treatment of the primary tumour, most patients are alive at five-year follow-up. There are not many population-based studies including both bone and soft tissue tumours, even though they are basically the same disease. The prognosis is still poor in axial and metastatic disease. Previous reports have suggested that the incidence of Ewing sarcoma in the paediatric population may be lower in Northern Europe compared to other parts of Europe and the United States. The prognosis of paediatric patients with bone sarcoma are nowadays generally good, but particularly in osteosarcoma, the prognostic effect of age is somewhat unclear. The surgical techniques of vertebral column resections, including those used for resection of malignant spinal tumours have evolved, with the invention of techniques using only a posterior approach. There are still not many reports that compare the anteroposterior approach to posterior-only approach. Aims Our aim in this study was to find out how the treatment of Ewing sarcoma is carried out in Finland and to find out what are the five-year overalland event-free survival rates and to find possible prognostic factors. Another aim of the study was to reveal the surgical treatment and its complications, particularly of axial tumours. We also aimed at establishing the incidence rates of Ewing sarcoma and other bone sarcomas in the paediatric and adolescent population in Finland and to establish the ten-year survival rates. Additionally, we aimed to report the results of a population-based material on paediatric vertebral column resection including patients operated via anteroposterior and posterior-only approach. Material and methods We identified all Finnish patients with Ewing sarcoma diagnosed during 1990-2009, all paediatric bone sarcoma patients diagnosed during 1991-2005 and all paediatric patients who underwent vertebral column resection during 2005-2009. The medical records were reviewed for detailed information on the disease, treatments, treatment complications and outcome and these data were analysed. The study is retrospective, nationwide and population-based. Results Seventy-six Ewing sarcoma patients with a median age of 17.8 years and a 2:1 male to female ratio were included in the final analyses of study I. Nineteen had a metastatic disease. The five-year sarcomaspecific survival rates were 70% for those with localized and 33% for those with metastatic disease (p=0.001). Older age (p=0.031), axial site of the primary tumour (p=0.016) and not receiving surgery with adequate margins for the primary tumour (p=0.033) were associated with impaired five-year sarcoma specific survival in univariate analyses. Fifty-seven patients underwent surgical treatment of the primary tumour. Eleven patients had early and 14 had late surgical complications, most of the late complications involving reconstructions of bone deficiencies. Five-year local-relapse free survival was significantly better with surgical resection margins free of tumour cells (84% vs. 33% with contaminated margins, p=0.003). The annual incidence rates of osteosarcoma, Ewing sarcoma and chondrosarcoma per million 0-18-year-old people in Finland during 1991-2005 were 3.6, 1.2 and 0.3, respectively. The patients with Ewing sarcoma were younger than those with osteosarcoma (median age in years 12.0 vs. 14.2, p=0.012) and more often had axial tumours (57% vs. 11%, p<0.001). The ten-year overall survival was 74% for osteosarcoma, 76% for Ewing sarcoma and 80% for chondrosarcoma. Between seven patients with paediatric spinal deformity that underwent vertebral column via anteroposterior approach and seven operated via posterolateral approach, there were no differences in