Predicting Tumor Recurrence with Early 18F-FDG PET-CT After Thermal and Non-Thermal Ablation

Area of Science:

• Oncology
• Radiology
• Nuclear Medicine

Background:

• Percutaneous image-guided ablation is a common treatment for primary and metastatic malignancies.
• Early assessment of ablation effectiveness is crucial for timely intervention and improved patient outcomes.
• 18-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) is a functional imaging technique that can detect metabolic activity.

Purpose of the Study:

• To evaluate the ability of early post-ablation 18F-FDG PET-CT scans to predict local tumor progression (LTP) after image-guided ablation.
• To assess the correlation between 18F-FDG avidity on early PET-CT and the development of LTP.
• To determine the impact of early PET-CT findings on local tumor progression-free survival (LTPFS).

Main Methods:

• Single-center retrospective review of patients undergoing image-guided ablation (microwave ablation, cryoablation, irreversible electroporation) between August 2018 and February 2024.
• Correlation of post-ablation 18F-FDG PET-CT findings (within 24 hours) with LTP development using chi-square test.
• Evaluation of LTPFS using Kaplan-Meier curves and multivariable Cox proportional hazards regression analysis.

Main Results:

• A total of 132 patients with 224 tumors were analyzed; 53.6% developed LTP.
• Nodular 18F-FDG avidity on early post-ablation PET-CT significantly correlated with LTP (p < 0.001), with a positive predictive value of 86.7%.
• Early 18F-FDG avidity was an independent predictor of LTP (HR = 2.355, p < 0.001) and decreased LTPFS.

Conclusions:

• Early post-ablation 18F-FDG PET-CT is a valuable tool for predicting local tumor progression after image-guided ablation.
• The presence of nodular 18F-FDG avidity suggests residual viable tumor and predicts a higher risk of LTP.
• Early detection of residual tumor may facilitate timely re-treatment, potentially improving LTPFS.