Objective:

To evaluate the effectiveness of fluorine-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) combined with contrast-enhanced computed tomography (CECT) in detecting local tumor progression after treatment for colorectal liver metastases.

Approach:

• Study Design: A single-center prospective observational cohort study involving 64 patients with 154 colorectal liver metastases treated with thermal ablation, hepatic resection, or both.
• Follow-Up: Patients underwent CECT, carcinoembryonic antigen (CEA) testing, and F-18 FDG PET/CECT 3 to 5 months post-treatment.
• Disease Progression Assessment: Disease progression was confirmed through histopathology, multidisciplinary team consensus, or extended follow-up of up to 3 years.

Key Findings:

• 66% of patients showed disease progression at first follow-up.
• Local tumor progression was identified in 25% of patients.
• F-18 FDG PET/CECT demonstrated greater diagnostic accuracy for local tumor progression compared to CECT alone.
• F-18 FDG PET/CECT identified all cases of local tumor progression, while CECT detected fewer than half.
• F-18 FDG PET/CECT was more accurate in identifying extrahepatic disease compared to CECT.
• CEA testing had a 43% false-negative rate for disease progression.

Interpretation:

Adding F-18 FDG PET/CT to standard care improved detection of local tumor progression and was more accurate for identifying extrahepatic disease, but did not enhance detection of new colorectal liver metastases.

Limitations:

• Single-center design.
• Relatively small and heterogeneous treatment groups.
• Potential selection bias.
• Reliance on multidisciplinary consensus rather than histopathologic confirmation for most diagnoses.

Conclusion:

Larger prospective studies are needed to confirm these findings.

Sources:

• European Radiology