Evaluation of metabolic response with F-18-FDG PET-CT in patients with advanced or recurrent thymic epithelial tumors

Methods: We evaluated 27 consecutive patients with advanced (16 patients) or recurrent (11 patients) TETs. All patients underwent F-18-FDG PET-CT before and after at least 3 cycles of chemotherapy. Maximum standardized uptake value (SUVmax) of all detected lesions was recorded and the most F-18-FDG avid lesion in each patient was selected for determination of percentage change of SUVmax (Delta SUVmax) in pre-and post-treatment scans. Tumor response was assessed by contrast-enhanced computed tomography (CE-CT) using RECIST criteria. Receiver operating characteristic (ROC) curve analysis was performed to define the optimal threshold of Delta SUVmax discriminating responders from non-responders.

Background: Patients with advanced or recurrent thymic epithelial tumors (TETs) often need several consecutive lines of chemotherapy. The aim of this retrospective monocentric study was to test whether F-18-Fluorodeoxyglucose positron emission tomography-computed tomography (F-18-FDG PET-CT) is able to monitor standard chemotherapy efficacy in those patients and whether metabolic response correlates with morphovolumetric response as assessed by Response Evaluation Criteria in Solid Tumor (RECIST).