Usefulness of positron emission tomography-computed tomography in pre-operative evaluation of intra-thoracic esophageal cancer

Background: The purpose of the study was to clarify the usefulness of positron emission tomography-computed tomography (PET-CT) for pre-operative evaluation of intra-thoracic esophageal cancer, especially in terms of regional lymph node status. Methods: Medical records of 93 consecutive cases from July 2007 to October 2012 were retrospectively reviewed. All patients underwent curative and complete esophagectomies for intra-thoracic esophageal cancer. We compared pre-operative maximum standard uptake values (SUVmax) of esophageal tumors and regional lymph nodes (LN) with other variables (chronic obstructive pulmonary disease, history of previous other primary cancer, gender, differentiation, and neoadjuvant therapy). In addition, the SUVmax of tumors and LNs were analyzed with pathologic findings. Results: There was no significant difference of each tumor and LN SUVmax according to factors including chronic lung disease, age, history of previous other cancer, differentiation, and gender. Pre-operative evaluations by PET-CT were not accurate (tumor sensitivity 76.4%, specificity 25%; LN sensitivity 45.2%, specificity 54.8%). Receiver operating characteristic analysis showed that LN metastasis could not be appropriately diagnosed with SUVmax (P=0.871). There was no difference in SUVmax between pathologically positive and negative LN subgroups. Tumor SUVmax correlated with the progression of esophageal cancer in patients without neoadjuvant therapy (P<0.001). However, LN SUVmax had no correlation with overall pathologic stage. After neoadjuvant therapy, there were significant decreases in SUVmax in both pathologically positive and negative LN subgroups (P=0.043, P=0.008). Conclusion: Surgery should not be withheld in N-stage according to PET-CT findings and carefully considered in conjunction with other conditions.