Childhood Soft Tissue Sarcoma Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Treatment of Newly Diagnosed Childhood Soft Tissue Sarcoma
Tumors of Peripheral Nerves
Malignant peripheral nerve sheath tumor
Malignant peripheral nerve sheath tumor arises in children with type 1 neurofibromatosis (NF1), and it arises sporadically.
Features with favorable prognosis include the following:[65,66,67,68]
- Smaller tumor size—In a multivariate analysis, only tumor size and nuclear p53 expression were found to be independent predictors of disease-specific survival.
- Localized disease; no metastasis at presentation—A retrospective review of 140 patients with malignant peripheral nerve sheath tumor from the MD Anderson Cancer Center included children and adolescents. The disease-specific survival at 10 years was 32%. In this series, presence of metastatic disease was associated with a much worse prognosis. For patients with localized disease, there was no significant difference in outcome between patients with and without NF1.
- Lower stage.
- Lower histologic grade.
- Extremity as the primary site.
It is not clear whether the absence of NF1 is a favorable prognostic factor as it has been associated with both favorable  and unfavorable outcomes.[65,66,68]
There is agreement that complete surgical removal of the tumor, whenever possible, is the mainstay of treatment. The role of radiation therapy is difficult to assess, but durable local control of known postsurgical microscopic residual tumor is not assured after radiation therapy. Chemotherapy has achieved objective responses in childhood malignant peripheral nerve sheath tumor. A large retrospective analysis of the German and Italian experience with malignant peripheral nerve sheath tumor reported that 65% of measurable tumors had objective responses to ifosfamide-containing chemotherapy regimens, but the analysis did not conclusively demonstrate improved survival for chemotherapy. This retrospective analysis also noted a trend toward improved outcome with adjuvant radiation therapy. A series of 37 young patients with malignant peripheral nerve sheath tumor and NF1 showed that most patients had large invasive tumors that were poorly responsive to chemotherapy; progression-free survival was 19% and 5-year OS was 28%. The role of adjuvant chemotherapy following resection of malignant peripheral nerve sheath tumor has not been prospectively evaluated.
Tumors of Uncertain Differentiation
Tumors of uncertain differentiation include the following tumor subtypes:
- Alveolar soft part sarcoma.
- Clear cell sarcoma of soft tissue.
- Desmoplastic small round cell tumor.
- Epithelioid sarcoma.
- Extrarenal rhabdoid tumor.
- Extraskeletal myxoid chondrosarcoma.
- Primitive neuroectodermal tumor (PNET)/extraskeletal Ewing tumor.
- Synovial sarcoma.
- Undifferentiated sarcoma; sarcoma, not otherwise specified (NOS).
Alveolar soft part sarcoma
This is a tumor of uncertain histogenesis. A consistent chromosomal translocation t(X;17)(p11.2;q25) juxtaposes the ASPSCR1 gene with the TFE3 gene.[70,71] In children, alveolar soft part sarcoma often presents with metastases  and sometimes has a very indolent course. A subset of renal tumors found in young people was previously considered to be renal cell carcinoma, but the subset now appears to be genetically related to alveolar soft part sarcoma.