Diagnostic and prognostic value of FDG PET-CT in patients with suspected recurrent thymic epithelial tumors.

This study aimed to evaluate the diagnostic and prognostic value of FDG PET/CT in patients with suspected recurrent thymic epithelial tumors (TETs). We retrospectively reviewed 83 patients with histopathologically proven TETs (50 thymomas; 33 thymic carcinomas) who underwent FDG PET/CT after surgery. The sensitivity and specificity of FDG PET/CT in detecting recurrence were calculated. The progression-free survival rate (PFS) was calculated by the Kaplan-Meier method. FDG PET/CT results were positive in 50 patients and negative in 33. Recurrent TETs were confirmed in 40 of 50 patients with positive PET/CT findings. The sensitivity and specificity of FDG PET/CT were 100% and 76.7%, respectively. Disease progression occurred in 28 patients during the follow-up. FDG PET/CT showed added prognostic value over the Masaoka stage and histopathology. Among patients with the same Masaoka stage, negative PET/CT was significantly associated with better PFS (P < 0.001). Similarly, among patients with the same histopathology, negative PET/CT was also associated with a significantly longer PFS (P < 0.001). FDG PET/CT demonstrated a good diagnostic performance in patients with recurrent TETs and had an important prognostic value in assessing the risk of disease progression.