The Usefulness of Pre-Radiofrequency Ablation SUVmax in 18F-FDG PET/CT to Predict the Risk of a Local Recurrence of Malignant Lung Tumors after Lung Radiofrequency Ablation

The aim of the present study was to assess the diagnostic usefulness of Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in the prediction of local recurrence of malignant lung tumors by analyzing the pre-radiofrequency ablation (RFA) maximal standardized uptake value (SUVmax). We performed a historical cohort study of consecutive malignant lung tumors treated by RFA from January 2007 to May 2008 at Okayama University Hospital. We selected only lung tumors examined by PET/CT within 90 days before RFA and divided them (10 primary and 29 metastatic) into 3 groups according to their tertiles of SUVmax. We calculated recurrence odds ratios in the medium group and the high group compared to the low group using multivariate logistic analysis. After we examined the relationship between SUVmax and recurrence in a crude model, we adjusted for some factors. Tumors with higher SUVmax showed higher recurrence odds ratios (medium group;1.84, high group;4.14, respectively). The tumor size also increased the recurrence odds ratio (2.67);we thought this was mainly due to selection bias because we excluded tumors less than 10mm in diameter. This study demonstrated the pre-RFA SUVmax in PET/CT may be a prognostic factor for local recurrence of malignant lung tumors.