Partially excised or recurrent lesions that do not pose a significant danger to vital organs may be monitored closely if other treatment alternatives are not available.[16,19,20,21,22] Whenever possible, however, the treatment of choice is complete resection.
Hemangiopericytoma (in infants and young children) and infantile fibrosarcoma
In children with infantile fibrosarcoma, preoperative chemotherapy has made possible a more conservative surgical approach; agents active in this setting include vincristine, dactinomycin, cyclophosphamide, and ifosfamide.[1,23] Responses to presurgical chemotherapy with similar agents have been reported in cases of infantile hemangiopericytoma.
Treatment of Childhood Soft Tissue Sarcoma with Adult-like Soft Tissue Sarcoma Biologic Characteristics
The pediatric neoplasms listed below exhibit biologic behavior that is similar to lesions in adults:
- Alveolar soft part sarcoma (ASPS).
- Clear cell sarcoma.
- Desmoplastic small round cell tumor.
- Epithelioid sarcoma.
- Extraosseous osteosarcoma.
- Fibrosarcoma in older children and adolescents.
- Hemangiopericytoma in older children and young adults.
- Malignant fibrous histiocytoma.
- Malignant peripheral nerve sheath tumor (MPNST).
- Mesenchymal chondrosarcoma.
- Synovial sarcoma.
- Undifferentiated soft tissue sarcoma.
- Vascular tumors: angiosarcoma, hemangioendothelioma, hemangiopericytoma in older children and young adults (aged >4 years), and lymphangiosarcoma.
Much of what is known about treating these tumors is derived from studies in adults. Standard treatment options for these tumors include the following:
- Complete surgical resection alone (if margins were tumor-free) or followed by re-excision if margins were positive.
- Surgical excision followed by postoperative radiation therapy or brachytherapy if tumor margins were positive and further resection is not possible.
Every attempt should be made to resect the primary tumor locally with negative margins.[24,25] If the original operation failed to achieve pathologically negative tissue margins, a second surgery may be indicated. Although combined surgery and radiation therapy have dramatically improved outcome in adults and children with soft tissue sarcomas over the past 20 years, the morbidity of high-dose radiation therapy should be considered in infants and young children with these tumors. The use of brachytherapy and intraoperative radiation therapy is under study.[8,27] Preoperative radiation therapy has been associated with excellent local control rates in adults;[28,29] this approach has not been used extensively in pediatric patients.
The role of adjuvant (postoperative) chemotherapy remains controversial. Virtually all trials of adjuvant chemotherapy in adults with soft tissue sarcoma report the results of treatment for all patients in aggregate. This may obscure important differences in chemosensitivity among histologic subtypes of soft tissue sarcoma. A retrospective analysis of neoadjuvant chemotherapy in adults with soft tissue sarcoma suggested a benefit for patients with larger tumors. The largest prospective pediatric trial failed to document any benefit of adjuvant chemotherapy with vincristine, dactinomycin, cyclophosphamide, and doxorubicin in children with grossly resected tumors. This trial also reported results in aggregate for a variety of soft tissue sarcomas. In patients with unresectable or metastatic disease treated with vincristine, dactinomycin, and cyclophosphamide, the overall survival (OS) and disease-free survival rates were 31% and 10%, respectively. Achieving complete responses after aggressive chemotherapy, radiation therapy, and surgery is possible in most patients with more advanced NRSTS.