Clinico-biological Study/Characterization of Rhabdomyosarcoma in Adolescents and Young Adults, 15-25-year-old Patients

Rhabdomyosarcoma (RMS) stands for the most frequent soft tissue sarcoma in children and, adolescents and young adults (AYA, 15-25-year-old population), accounting for approximately half of the whole soft tissue sarcomas in these populations.. Conversely, RMS represents a very small proportion of the soft tissue sarcomas in adults (3%), that is less than 1% of all solid cancers of adults. To date, previous studies undertaken among the paediatric population have pointed out several prognostic factors such as tumor localisation, tumor invasiveness at diagnosis, tumor size, histological subset, and treatment plans. Age at diagnosis remains an independent prognostic factor. RMS management is consensual in Europe for paediatric population, essentially based on the protocol RMS 2005 within the framework of the European Paediatric Soft tissue sarcoma Study Group (EpSSG). Care in AYAs remain heterogeneous and are either achieved in paediatric department, according to EpSSG guidelines, or in oncology department, known as "adult unit", depending on ESMO (European Society for Medical Oncology), which are non-specific recommendations for the management of rhabdomyosarcoma. No consensus has been published yet for RMS in AYA despite the growing interest in cancers in AYA population - topic.supported by the French National Cancer Institute (INCa) - and the increasing network between paediatricians and adult-oncologists. Thus management of RMS in AYA remains patchy/unequal depending on the type of care unit. Herein, with the support of the Oscar Lambret Center, we aim at assessing and identifying clinico-biological prognostic factors of rhabdomyosarcoma in AYA. Eventually, we hope to offer a standardized treatment to this population. Data collected from medical file will be anonymised in a confidential database of which the recipient is the sponsor of the study. The ancillary study will aim at characterizing the molecular profile of the difficult-to-classify RMS subtypes (fusif