Background: In order to investigate the value of FDG positron emission tomography-computed tomography (PET-CT), FDG PET (reviewed side-by-side with CT), and metabolic parameters in the assessment of lymph node status and prognosis.
Methods: Fifty-five subjects with lymph node positive (N1) and 26 subjects with lymph node negative (N0) disease were included. In the slice with the maximum FDG uptake of the tumor, the axial area of the primary tumor, the maximum diameter of the tumor, and the mean and maximum standardized uptake values were measured.
Results: Fused PET-CT correctly characterized 289 of 325 lymph node groups (accuracy 89%) compared to 273 of 325 with PET (accuracy 84%). In lymph node staging (N0 vs. N1), PET-CT (accuracy 83%) was more accurate than PET (accuracy 78%). Among the metabolic parameters, the tumor diameter measured on PET-CT was the best predictor of lymph node stage (N0 vs. N1: accuracy 86%; threshold 25.5 mm) and overall survival. However, the highest accuracy of lymph node staging (N0 vs. N1) was achieved with the synergistic combination of visual analysis and primary tumor diameter measurements (accuracy 95%).
Conclusions: PET-CT increases accuracy of lymph node staging in esophageal adenocarcinoma compared to PET. The primary tumor diameter further improves accuracy in lymph node staging and was shown to be an independent predictor of overall survival.