Sarcomas of Bone
Summary of Key Points
Incidence and Epidemiology
• More than 2800 new cases of bone sarcoma are diagnosed annually in the United States.
• No specific etiologic agents are identified in the majority of cases.
• Secondary neoplasms are related to known oncogenic factors. (e.g., ionizing radiation, alkylating chemotherapy agents, combinations of both).
• Hereditary cancer syndromes (tumor suppressor genes) are responsible for some cases.
Diagnosis and Radiographic Staging
• Plain radiographs are recommended.
• Magnetic resonance imaging (MRI) scan of primary tumor is the best radiographic study to obtain.
• Chest computed tomography (CT) is indicated to evaluate for pulmonary metastases.
• Whole-body technetium-99m (99mTc) bone scan is indicated to evaluate for metastases to other bones.
• Positron emission tomography (PET) scanning is controversial and has yet to be generally accepted.
• Needle or open biopsy is necessary for a tissue-specific diagnosis and to determine histologic grade.
• In the pathology review, immunohistochemistry and cytogenetics are important.
Prognostic Factors
• Metastasis at presentation is a worse prognostic finding.
• Histologic grade is the next most significant prognostic indicator.
• Size is less significant, but lesions larger than 10 cm in diameter have a poor prognosis.
• Tumor response to neoadjuvant chemotherapy is important in osteosarcoma and Ewing sarcoma.
