Initial McGill experience with fluorodeoxyglucose pet/ct staging of soft-tissue sarcoma

Area of Science:

• Oncology
• Radiology
• Medical Imaging

Background:

• Soft-tissue sarcoma frequently metastasizes to the lungs.
• The diagnostic yield of positron-emission tomography (PET) for detecting lung metastases not evident on chest computed tomography (CT) is not well-established.

Purpose of the Study:

• To evaluate the effectiveness of fluorodeoxyglucose (FDG) PET imaging in detecting metastatic disease in patients with soft-tissue sarcoma during initial staging.
• To determine if PET imaging alters patient management compared to standard chest CT.

Main Methods:

• Retrospective review of 75 soft-tissue sarcoma cases (excluding specific subtypes like Ewing sarcoma, rhabdomyosarcoma, GIST).
• Patients included had undergone diagnostic chest CT as part of staging.
• Exclusion of cases for follow-up, response assessment, or recurrence imaging.
• Review of clinical charts and pre-treatment imaging.

Main Results:

• FDG PET imaging was negative for distant disease in 64 out of 75 patients.
• Chest CT detected metastases in 7 cases where PET was negative (88% negative predictive value for PET).
• PET imaging upstaged only 1 patient (1.3%) and did not alter management for patients with known metastatic disease.

Conclusions:

• Routine use of FDG PET for initial staging of soft-tissue sarcoma offers limited added value over chest CT.
• PET imaging is unlikely to alter patient management in the majority of soft-tissue sarcoma cases.
• PET may be beneficial in specific, yet-to-be-defined circumstances.