Sarcomas of soft tissue and bone.

Sarcomas arise primarily from mesenchymal structures at any site in the body, even within visceral stroma and neurovascular bundles. Sarcomas have been associated with prior radiation therapy, toxic exposures, and genetic conditions and soft tissue sarcomas have been distinguished from bone sarcomas. For localized soft tissue sarcoma, tumor grade is the most important prognostic variable. Low-grade tumors are generally cured by wide surgical excision, but there is a significant rate of both local recurrence and development of distant metastasis in high-grade lesions. The treatment of soft tissue sarcoma histologic subtypes is generally similar grade-for-grade, with the exception of rhabomyosarcoma, Kaposi's sarcoma, and mesothelioma. Tumor location strongly influences resectability. Radiation therapy has been used successfully in conjunction with conservative surgery to improve local control rates for soft tissue sarcomas, particularly in extremity lesions. Currently, adjuvant chemotherapy remains unproven for most adult soft tissue sarcomas, but is established in the treatment of rhabdomyosarcomas, osteosarcomas, and Ewing's sarcomas.