Table 3.
Summary of Treatment Recommendations for Specific Histotypes
| Histotype | Clinical Features | EpSSG Treatment Recommendations |
|---|---|---|
| Adult-type NRSTS requiring a specific therapeutic approach | ||
| Alveolar soft part sarcoma | Highly malignant; conventional chemotherapy is ineffective | Surgery (± radiotherapy) for localized resectable tumors (no adjuvant chemotherapy). Targeted agents in case of unresectable/metastatic disease. Promising data on immune checkpoint inhibitors |
| Clear cell sarcoma | Highly malignant, no response to chemotherapy | Local therapy (surgery ± radiotherapy). Promising results with immunotherapy |
| Dermatofibrosarcoma protuberans | Generally low-grade, small, superficial | Wide surgery is the mainstay. Imatinib mesylate in unresectable or metastatic cases (very rare in pediatric age) |
| Malignant soft tissue tumors requiring a specific therapeutic approach | ||
| Undifferentiated soft part sarcoma | Debated if it is really a clinical entity | Treatment according to strategy for rhabdomyosarcoma (9 courses of IVA), or ifosfamide-doxorubicin as for high-risk adult-type NRSTS |
| Undifferentiated (embryonal) sarcoma of the liver | Generally good response to conventional chemotherapy | Complete surgery is the mainstay. Patients with initial resection: 4–6 courses of IVA ± doxorubicin. Patients with unresectable tumor: 9 courses of IVA ± doxorubicin to shrink the tumor and enable resection |
| Extra-cranial malignant rhabdoid tumors | Highly aggressive tumors of young children | Dose-intensive multi-drug chemotherapy every 2 weeks (eg VDCy-IE). Local therapy as soon as possible (taking the patient’s age into account) |
| Desmoplastic small round cell tumors | Abdominal mass widely disseminated at diagnosis; poor prognosis | Intensive chemotherapy (eg VDCy-IE, or IVADo or IrIVA), surgery, whole abdominal radiotherapy, maintenance therapy |
| Soft tissue tumors of intermediate malignancy requiring specific therapeutic recommendations | ||
| Desmoid-type fibromatosis | Intermediate malignancy, local aggressiveness | Wait-and-see for non-evolving disease; low-dose methotrexate plus vinblastine in cases with tumor progression |
| Inflammatory myofibroblastic tumor | Intermediate malignancy | Surgery remains the mainstay of treatment In cases of advanced disease: vinblastine-methotrexate or targeted therapy (eg ALK inhibitors) |
| Infantile fibrosarcoma | Low malignant potential; initial rapid growth and huge size at onset | Surgery remains the mainstay of treatment VA chemotherapy and NTRK inhibitors are both options for patients with advanced localized disease. |
Abbreviations: IVA, ifosfamide, vincristine, actinomycin-D; IVAd, ifosfamide, vincristine, doxorubicin; VDCy, vincristine–doxorubicin–cyclophosphamide; IE, ifosfamide–etoposide; IVADo, ifosfamide, vincristine, actinomycin-D, doxorubicin; IrIVA, irinotecan, ifosfamide, vincristine, actinomycin-D; VA, vincristine–actinomycin-D.