Positron emission tomography in musculoskeletal sarcomas

Purpose of review: To summarize recent advances in the use of positron emission tomography in the evaluation and treatment of musculoskeletal sarcomas. Recent findings: Most radiographic methods, such as magnetic resonance imaging or computed tomography, cannot distinguish the histologic grade of musculoskeletal sarcomas and are inaccurate in predicting response to neoadjuvant therapy. [18F]Fluorodeoxy-D-glucose positron emission tomography is a noninvasive imaging modality that measures the metabolic activity of malignant tissue semiquantitatively, improving the ability to distinguish benign or low-grade malignancies from high-grade sarcoma. Recent retrospective analyses of soft tissue sarcomas and Ewing sarcomas have demonstrated that [18F]fluorodeoxy-D-glucose positron emission tomography changes with neoadjuvant chemotherapy are associated with recurrence-free survival. The optimal timing of [18F]fluorodeoxy-D-glucose positron emission tomography to determine metabolic response and cut-points to distinguish metabolic response remain incompletely defined. [18F]Fluorodeoxy-D-glucose positron emission tomography may have additional roles in the initial staging of sarcomas, and detecting local and distant recurrence. Summary: [18F]Fluorodeoxy-D-glucose positron emission tomography evaluation may refine the preoperative characterization of musculoskeletal sarcomas, and improve disease staging, assessment of response to neoadjuvant therapy and detection of recurrence. Further prospective studies are necessary to determine the optimal utilization of [18F]fluorodeoxy-D-glucose positron emission tomography.