Preoperative Nodal (18)F-FDG Avidity Rather than Primary Tumor Avidity Determines the Prognosis of Patients with Advanced Gastric Cancer

PURPOSE: This study investigated whether the metabolic avidity of primary tumors and/or metastatic lymph nodes (LNs) measured by (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) was related to survival after surgery in patients with advanced gastric cancer (AGC). MATERIALS AND METHODS: One hundred sixty-eight patients with AGC who underwent preoperative (18)F-FDG PET/CT and curative resection were included. The (18)F-FDG avidity of the primary gastric tumor and LNs was determined quantitatively and qualitatively. The diagnostic performance of (18)F-FDG PET/CT was calculated, and the prognostic significance of (18)F-FDG avidity for recurrence-free survival (RFS) and overall survival (OS) was assessed. RESULTS: In all, 51 (30.4%) patients experienced recurrence, and 32 (19.0%) died during follow-up (median follow-up duration, 35 months; range, 3–81 months); 119 (70.8%) and 33 (19.6%) patients showed (18)F-FDG-avid primary tumors and LNs, respectively. (18)F-FDG PET/CT showed high sensitivity (73.8%) for the detection of advanced pathologic T (pT ≥3) stage and high specificity (92.2%) for the detection of advanced pN (≥2) stage. (18)F-FDG avidity of LNs was significantly associated with RFS (P=0.012), whereas that of primary tumors did not show significance (P=0.532). Univariate and multivariate analyses revealed that (18)F-FDG avidity of LNs was an independent prognostic factor for RFS (hazard ratio=2.068; P=0.029). CONCLUSIONS: (18)F-FDG avidity of LNs is an independent prognostic factor for predicting RFS. Preoperative (18)F-FDG PET/CT can be used to determine the risk and prognosis of patients with AGC after curative resection.