Treatment of Nonmetastatic Childhood Soft Tissue Sarcoma
Chemotherapy for extraosseous osteosarcoma has not been well studied. Treatment has previously been recommended to follow soft tissue sarcoma guidelines rather than guidelines for osteosarcoma of bone. Extraosseous osteosarcoma may be more chemosensitive in young patients than in adults. A retrospective analysis of the German Cooperative Osteosarcoma Study identified a favorable outcome for extraskeletal osteosarcoma treated with surgery and conventional osteosarcoma chemotherapy. (Refer to the PDQ summary on Osteosarcoma/Malignant Fibrous Histiocytoma of Bone for more information.)
Malignant peripheral nerve sheath tumor
A large retrospective analysis of the German and Italian experience with MPNST identified incomplete resection, large tumor size, tumor invasiveness, nonextremity primary site, and clinical diagnosis of neurofibromatosis as unfavorable prognostic findings. There was a trend toward improved outcome with adjuvant radiation therapy. While 65% of measurable tumors had objective responses to ifosfamide-containing chemotherapy regimens, the analysis did not conclusively demonstrate improved survival for chemotherapy. A series of 37 young patients with MPNST and neurofibromatosis type 1 (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%. Another series of older patients with MPNST found that those with NF1 had a worse prognosis than those without NF1.
Synovial sarcoma appears to be more sensitive to chemotherapy than many other NRSTSs. The most commonly used regimens for the treatment of synovial sarcoma incorporate ifosfamide and doxorubicin.[25,36,48] Children with synovial sarcoma have a higher probability for both event-free survival (EFS) and OS than children with other types of NRSTS.[49,50] A German randomized trial suggested a benefit for adjuvant chemotherapy in children with synovial sarcoma. A meta-analysis also suggested that chemotherapy may improve EFS but could not confirm improvement in OS. Many treatment centers advocate adjuvant chemotherapy following resection of synovial sarcoma in children and young adults; unequivocal proof of the value of this strategy from prospective, randomized clinical trials is lacking. A study of 21 patients with small (<1 cm), localized synovial sarcomas showed an excellent survival rate with no metastatic events; only one patient received chemotherapy. A retrospective analysis of synovial sarcoma in children treated in Germany and Italy identified tumor size (>5 cm or <5 cm in greatest dimension) as an important predictor of EFS. In this analysis, local invasiveness conferred an inferior probability of EFS, but surgical margins did not predict outcome.
Undifferentiated soft tissue sarcoma
Patients with undifferentiated soft tissue sarcoma were eligible for participation in rhabdomyosarcoma trials coordinated by the Intergroup Rhabdomyosarcoma Study Group and the Children's Oncology Group (COG) from 1972 to 2006. The rationale was the observation that patients with undifferentiated soft tissue sarcoma had similar sites of disease and outcome compared with those with alveolar rhabdomyosarcoma. Therapeutic trials for adults with soft tissue sarcoma include patients with undifferentiated soft tissue sarcoma and other histologies, which are treated similarly, using ifosfamide and doxorubicin, and sometimes with other chemotherapy agents, surgery, and radiation therapy. The COG is studying the use of a combination of surgery and/or radiation therapy, with or without ifosfamide and doxorubicin, for patients with undifferentiated soft tissue sarcoma in its open protocol COG-ARST0332, which is for patients with NRSTS.