The value of adjuvant chemotherapy in the management of sarcomas in children.

Sarcomas of childhood rank fifth in incidence of malignant tumors in children younger than 15 years. Among the soft tissue sarcomas, approximately 50% are rhabdomyosarcomas. The remainder represent a heterogeneous group of diverse sarcomas which are not unique to children and include fibrosarcoma, synoviosarcoma, malignant fibrous histiocytoma, malignant schwannoma, angiosarcoma, leiomyosarcoma, and others. The most common bone cancers in childhood are osteosarcoma and Ewing's sarcoma. Although a multidisciplinary approach utilizing surgery, irradiation, and combination chemotherapy is routinely used in management of virtually all children with solid tumors, the value of adjuvant chemotherapy in select bone and rare soft tissue sarcomas is currently being tested. Multiagent chemotherapy including vincristine, dactinomycin, cyclophosphamide, and Adriamycin (doxorubicin) contribute to cure rates in 65% to 75% of children with localized rhabdomyosarcoma, Stages I to III, when combined with surgery and/or irradiation. Other drugs which hold promise include platinum, DTIC, methotrexate, and VP-16. The efficacy of similar drugs in the rarer pediatric soft tissue sarcomas other than rhabdomyosarcoma and its variants requires prospective randomized trials evaluating histologic grade, tumor size, and nodal status. It has been suggested that the high-grade sarcomas presenting with minimal tumor bulk are most sensitive to combined radiotherapy-chemotherapy, whereas the low-grade sarcomas are more resistant to such therapy. Tumor cell heterogeneity contributes to biologic diversity and response to treatment. Chemotherapy as adjuvant therapy to irradiation is currently recommended and utilized for Ewing's sarcoma with survival rates approaching 80%, and disease-free survival of approximately 75% for those with localized disease. Children with widespread and metastatic disease at presentation fare less well. Although multiple single agents exhibit response rates ranging from 40% to 60%, including cyclophosphamide, Adriamycin, dactinomycin, BCNU, mithramycin, and 5-fluorouracil, new and more effective agents are needed. Controversy regarding the value of multiagent chemotherapy in osteosarcoma has stimulated prospective randomized trials. Evaluation of local control rates as well as sites and occurrence of metastases are essential in assessing the contribution of aggressive combined modality therapy in the pediatric sarcomas. Emphasis on refinement of therapy in determining the risk/benefit ratio from adjuvant chemotherapy in pediatric sarcomas is mandatory. Enhancement of early local reactions is apparent when adjuvant chemotherapy is used with local radiotherapy.(ABSTRACT TRUNCATED AT 400 WORDS)