Current approaches to therapy: soft tissue sarcomas other then rhabdomyosarcoma in children and adolescents

Sarcomas in children and adolescents under 18 years of age are rare diseases and include various different histiotypes that include soft tissue sarcomas of “pediatric-type” (i.e., rhabdomyosarcoma), “adult-type” (i.e., synovial sarcoma, malignant peripheral nerve sheath tumor), special entities (infantile fibrosarcoma, desmoid tumor, dermatofibrosarcoma protuberans), and bone sarcomas. The group of “non-rhabdomyosarcoma soft tissue sarcomas” (NRSTS) gathers all soft tissue sarcomas, except rhabdomyosarcoma and Ewing sarcoma, occurring during childhood and adolescence. The incidence varies with age, but NRSTS are more frequent during adolescence and early adulthood. Sensitivity to medical therapy depends on the disease type, which must be taken into account in the therapeutic strategy. The age of the patient, the tumor extension, and the potential resectability of the primary tumor also play important roles. Survival for most of these sarcomas is good, although lower in adolescents than in younger patients; certain histologies and metastatic presentations are difficult to cure with current treatments. In these cases, patients should be included in biology-driven protocols as soon as possible. Moreover, recent clinical developments of a new class of compounds blocking, for example, NTRK molecular pathway, which are still currently under early clinical investigation, give an important hope to find a specific new way to treat patients with such tumors. In this chapter, the authors describe European and North American pediatric strategies in the treatment of pediatric and adolescent NRSTS.