Treatment effects in pediatric soft tissue and bone tumors: practical considerations for the pathologist.

Dramatic improvements in survival for children with cancer have led to increased numbers of posttreatment pathologic specimens, particularly in bone and soft tissue sarcomas. Current therapeutic protocols in North America require specific pathologic classification and stratify patients based on clinical, biologic, and pathologic features. For osteosarcoma, the pathologic response to therapy predicts prognosis and modifies the treatment regimen. Ongoing studies aim to assess the response to therapy and outcome in other types of soft tissue and bone tumors. The pathologic evaluation of pretreatment and posttreatment specimens is critical for therapeutic decisions and prognostic assessment. A standardized approach to posttherapy pathologic specimens, with attention to appropriate use of ancillary tests, and assessment of clinical and biologic significance of therapy-induced pathologic changes has significance for patient management and treatment protocols.