Twenty-five-year experience of treating synovial sarcoma in children

Introduction. Synovial sarcoma (SS) is a rare and aggressive tumor of the soft tissues comprising about 4 % of all soft tissue sarcomas. While SS can develop at any age, mostly it occurs in teenagers and young adults. In children, SS develops relatively rarely but it is characterized by aggressive course and high metastasis rate which makes it a serious problem of pediatric oncology. Aim. To compare results of 3 protocols of treatment of pediatric patients with SS (protocol of the L.A. Durnov Research Institute of Pediatric Oncology and Hematology of the N.N. Blokhin National Medical Research Center of Oncology, Children’s Oncology Group (COG) protocol, and CWS-2009 protocol). Materials and methods. Results of treatment of children with SS of the soft tissues (n = 103) performed at the L.A. Durnov Research Institute of Pediatric Oncology and Hematology of the N.N. Blokhin National Medical Research Center of Oncology between 1999 and 2024 in accordance to the 3 protocols – of this Institute, COG and CWS-2009 – were analyzed. Results. The best overall survival was achieved using the COG and CWS-2009 protocols with minimal differences for short polychemotherapy courses. For localized disease stage in patients receiving treatment per these protocols, 100 % overall survival was achieved. After radical surgical treatment, radiotherapy was unnecessary. Conclusion. According to the obtained data, treatment of localized SS per the COG and CWS-2009 protocols leads to overall survival of 100 %. Improvement of 2-year overall survival in patients with disseminated SS when using the CWS-2009 protocol is likely associated with addition of metronomic therapy. To decrease hematological toxicity and to optimize polychemotherapy courses without increasing intervals between the courses, hemopoietic support at the consolidation stage can be used.