Thoracic Lymph Node Involvement in Adenocarcinoma of the Esophagogastric Junction and Lower Esophageal Squamous Cell Carcinoma Relative to the Location of the Proximal End of the Tumor

It is difficult to determine preoperatively whether upper/middle thoracic lymphadenectomy is necessary in patients with adenocarcinoma of the esophagogastric junction (AEG) or lower esophageal squamous cell carcinoma (ESCC). Here, we investigated whether stratification based on the location of the proximal end of the tumor, as assessed using preoperative computed tomography (CT) images, would be useful for predicting upper/middle thoracic lymph node involvement for AEG and lower ESCC. A total of 142 patients with AEG and lower ESCC treated by R0-1 surgical resection via a thoracotomy was retrospectively investigated. The location of the proximal end of the tumor in comparison with the vena cava foramen (VCF) was decided by inspecting preoperative CT images and then correlated with upper/middle thoracic lymph node involvement. The incidence of upper/middle thoracic lymph node involvement was low in AEG and ESCC tumors having proximal ends below the VCF (0 %, 0 of 13, and 5.9 %, 1 of 17, for AEG and ESCC, respectively). In contrast, when the tumors' proximal ends were above the VCF, patients had higher frequencies of upper/middle thoracic lymph node involvement (36.4 %, 8 of 22, and 37.8 %, 34 of 90, for AEG and ESCC, respectively). Multivariate analysis showed that the location of the proximal end of the tumor is an independent risk factor related to upper/middle thoracic lymph node involvement (odds ratio 14.3, 95 % confidence interval 1.76-111, p = 0.013), whereas other clinical factors (cT, cN, tumor length, and histologic types) are not. This manner of stratification using preoperative CT images could be useful in deciding the extent of thoracic lymphadenectomy in both AEG and ESCC.