Fluorodeoxyglucose positron emission tomography in leiomyosarcoma: imaging characteristics.

OBJECTIVE

Leiomyosarcoma, a malignant neoplasm of smooth muscle, accounts for 7% of the sarcomas. Patients with leiomyosarcoma tumors have an average survival of 5 years. These tumors, which are derived from mesenchymal tissues, are difficult to diagnose, and treatment options remain controversial. The relatively rare incidence of this soft tissue sarcoma subtype has limited the number of patients available for studies and research. This study examines whether the imaging characteristics of positron emission tomography (PET) with radiolabeled fluorodeoxyglucose (FDG) provide a reliable, noninvasive means to predict tumor behavior in patients with leiomyosarcomas.

METHODS

[18F]-FDG-PET was performed on the tumors of participating patients before the neoadjuvant chemotherapy or resection, and a maximum tumor standard uptake value (SUVmax) was calculated.

RESULTS

The SUVmax was correlated with tumor grade (P=0.001) and tumor size as greatest dimension (P=0.004). Analysis of these data indicated the potential effectiveness of FDG-PET imaging in predicting tumor grade.

CONCLUSION

In leiomyosarcoma, the SUVmax from FDG-PET is a likely predictor of tumor behavior. The results of this study suggest that a large (by greatest dimension) intermediate grade tumor is expected to have the same predicted outcome as a high-grade tumor and should be treated in the same manner, as they share the same prognosis by definition of tumor grade. Improvements made in the clinical treatment of leiomyosarcomas by use of FDG-PET imaging data may lead to an increase in patient survival.