General Information About Osteosarcoma and Malignant Fibrous Histiocytoma (MFH) of Bone
Larger tumors have a worse prognosis than smaller tumors.[10,26] Tumor size has been assessed by the longest single dimension, by the cross-sectional area, or by an estimate of tumor volume; all have correlated with outcome. Serum lactate dehydrogenase (LDH), which also correlates with outcome, is a likely surrogate for tumor volume.
Presence of clinically detectable metastatic disease
Patients with localized disease have a much better prognosis than those with overt metastatic disease. As many as 20% of patients will have radiographically detectable metastases at diagnosis, with the lung being the most common site. The prognosis for patients with metastatic disease appears to be determined largely by the site(s), the number of metastases, and the surgical resectability of the metastatic disease.[28,29]
Adequacy of tumor resection
Resectability of the tumor is a critical prognostic feature because osteosarcoma is relatively resistant to radiation therapy. Complete resection of the primary tumor and any skip lesions with adequate margins is generally considered essential for cure. A retrospective review of patients with craniofacial osteosarcoma performed by the German-Austrian-Swiss osteosarcoma cooperative group reported that incomplete surgical resection was associated with inferior survival probability.[Level of evidence: 3iiB] For patients with axial skeletal primaries who either do not have surgery for their primary tumor or who have surgery resulting in positive margins, radiation therapy may improve survival.[14,35] In a European cooperative study, the size of the margin was not significant. However, having both the biopsy and resection at a center with orthopedic oncology experience conferred a better prognosis.