The aim of the study was to evaluate prospectively the clinical impact of 2-(18F)-fluoro-2-deoxy-D-glucose (18F-FDG) PET/computed tomography (CT) on the pretreatment assessment of patients with colorectal lung metastasis before radiofrequency (RF) ablation.Methods
The institutional review board approved this prospective study. The eligibility criteria for lung RF ablation were the presence of five or fewer colorectal lung metastases with a maximum tumor size of 3 cm and absence of extrapulmonary lesions. Lung RF ablation candidates who underwent pretreatment PET/CT studies were included. The incidence of detection of unexpected recurrent lesions on PET/CT was evaluated, along with its impact on subsequent treatments. Factors linked with the incidence of unexpected recurrent lesions were evaluated using univariate and multivariate analyses.Results
Between October 2008 and June 2011, 60 patients were enrolled. Among the unexpected abnormal 18F-FDG accumulations found in 13 patients (21.7%), presence of extrapulmonary lesions was proved in 12 patients (20.0%, 12/60), prompting treatment strategy changes. One false-positive case was found (1.7%, 1/60). The sensitivity, specificity, and accuracy in detecting unexpected lesions by PET/CT were, respectively, 100, 97.9, and 98.3%. Elevation of the serum carcinoembryonic antigen level (>6.0 ng/ml) was the only significant factor linked with unexpected lesions in both univariate (P=0.02) and multivariate analyses (P=0.02).Conclusion
A PET/CT study should be performed in patients with colorectal lung metastasis before selecting them for lung RF ablation, especially when the carcinoembryonic antigen level is elevated.