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 (SUV_max) 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 SUV_max 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 SUV_max 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 SUV_max of the primary tumor helped identify T1 tumor, and the SUV_max of the regional lymph nodes correlated with the severity of nodal involvement.