Positron Emission Tomography-Computed Tomography in Predicting Locoregional Invasion in Esophageal Squamous Cell Carcinoma

Background. In order to clarify the role of positron emission tomography-computed tomography (PET/CT) in thoracic esophageal squamous cell carcinoma we investigated its value in predicting locoregional invasion. Methods. Forty-five patients receiving curative esophagectomy and lymph node dissection were included. The relationship between PET/CT findings and pathology results were studied. Correlation between nodal uptake and the modified lymph node staging, which is based on number of involved nodes (N0 = no nodes; N1 = 1 to 3 nodes; N2 = more than 3 nodes), was evaluated. Results. The mean maximal standardized uptake value (SUVmax) was 5.09 +/- 4.00 in T1, 14.17 +/- 2.46 in T2, 13.32 +/- 3.96 in T3, and 10.37 +/- 1.94 in T4 primary tumor. The SUVmax was significantly lower in stage T1 tumors than in stage T2 and T3 tumors. For regional nodal involvement, PET/CT findings significantly correlated with pathology results. However, the sensitivity, specificity, and accuracy of PET/CT were only 57.1%, 83.3%, and 71.1%, respectively, and even lower for detecting nonregional lymph node metastasis. When stratified by the modified staging system, the mean SUVmax was 0.64 +/- 1.60 in N0, 1.43 +/- 2.08 in N1, and 4.67 +/- 4.32 in N2 regional lymph node metastases, and was significantly higher in patients with N2 metastasis than in patients with N0 and N1 metastases. Conclusions. Locoregional invasion in esophageal cancer can be predicted by PET/CT. The SUVmax of the primary tumor helped identify T1 tumor, and the SUVmax of the regional lymph nodes correlated with the severity of nodal involvement.