18F-FDG PET/CT-based recurrence patterns and survival outcomes in esophageal carcinoma: a single center experience.

BACKGROUND: This study aimed to evaluate differences among three patient groups with suspected recurrent esophageal carcinoma, defined by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) findings, in quantitative and semiquantitative PET/CT parameters and serum tumor markers, and to assess their impact on progression-free survival (PFS) and overall survival (OS). PATIENTS AND METHODS: This retrospective cohort study included 77 patients with positive 18F-FDG PET/CT findings between January 2014 and December 2025. Based on 18F-FDG PET/CT findings, patients were classified into three groups: G1 (isolated locoregional recurrence), G2 (isolated metastases), and G3 (both locoregional disease and metastases). Semiquantitative and quantitative 18F-FDG PET/CT parameters, histopathological characteristics, and blood tumor marker levels were compared among the groups. For survival analysis, patients were stratified into low and high groups according to the median value of each parameter. RESULTS: Elevated carcinoembryonic antigen (CEA) levels were significantly more frequent in G2 and G3 compared with G1 (p = 0.005), while no significant difference was observed for carbohydrate antigen 19-9 (CA19-9) levels (p = 0.280). Significant differences in all analyzed 18F-FDG PET/CT parameters were found among the three groups, with the highest values in G3. Patients with lower maximal standardized uptake values (SUVmax) and SUVmean values demonstrated significantly longer PFS and OS. Lower metabolic tumor volume (MTV) and total lesion glycolysis (TLG) values were associated with significantly longer progression-free survival (PFS), while overall survival (OS) was also longer, although without statistical significance. CONCLUSIONS: Studies stratifying patients by isolated locoregional recurrence, isolated metastases, and combined locoregional/metastases on 18F-FDG PET/CT remain limited. Our findings suggest that disease spread patterns and semiquantitative/quantitative 18F-FDG PET/CT parameters may provide important prognostic value in patients with esophageal carcinoma.