[Analysis on CT in diagnosis of lymph node metastasis of thoracic esophageal cancer with minimum diameter greater than 1 cm].

Objectives: To evaluate the diagnostic value of CT for lymph node metastasis of thoracic esophageal carcinoma with a diameter of more than 1 cm, and to find the optimal diagnostic index by comparing relevant CT indexes. Methods: Totally 80 patients with pathologically proved thoracic esophageal cancer with preoperative CT examination revealed lymph node diameter greater than 1 cm admitted at Department of Thoracic Surgery, the First Affiliated Hospital of University of Science and Technology of China from January 2016 to January 2018 were enrolled in this study. There were 70 males and 10 females, aging of (60±14) years (range: 40-85 years). According to the pathological result of lymph nodes, all the patients and lymph nodes were divided into two groups (N+group: 47 patients, 62 lymph nodes; N-group: 33 patients, 39 lymph nodes). The average number of dissected lymph nodes were 21±4 and 101 lymph nodes' diameter were greater than 1 cm. The clinicopathologic factors, postoperative complications, lymph node dissection and relevant CT indexes like the minimum diameter of lymph nodes (Min D), the maximum diameter of lymph node (Max D), lymph node axial ratio(LAR), the enhancement of lymph node (ELN) and the boundary of lymph node (BLN) were compared. The clinicopathological data, lymph node dessection and CT parameters of the two groups were compared by t test, χ(2) test or Wilcoxon rank sum test. Receiver operating characteristic (ROC) curve analysis was used to compare the ability to predict lymph node metastasis between Min D, Max D, LAR, ELN and BLN. Multiple Logistic regression analysis were performed to determine the independent variables for prediction of lymph node metastasis. Results: The difference of tumor segmentation, pN stage, pTNM stage, total number of metastatic lymph nodes, total number of abdominal lymph node metastases, Min D, Max D, ELN and BLN between the two groups were statistically significant. The results of univariate and multivariate analyses showed that gender ( OR= 0.128, 95 %CI : 0.019 to 0.858, P= 0.034), pTNM stage ( OR= 1.514, 95 %CI : 1.020 to 2.247, P= 0.039), Min D ( OR= 0.102, 95 %CI : 0.010 to 0.995, P= 0.050) and LAR ( OR= 0.195, 95 %CI : 0.052 to 0.731, P= 0.015) were the independent relative factors. The area under the curve of ROC curve analysis of Min D, Max D, LAR, ELN and BLN were 0.679, 0.666, 0.561, 0.650 and 0.820, respectively. BLN was the best CT index to diagnosis lymph node metastasis, while the accuracy of dignosis of lymph node metastasis of BLN was 97.0%. The Youden index of Min D, Max D and LAR were 1.25 cm, 1.64 cm and 0.77, respectively. Combining the BLN and ELN had a higher diagnostic rate (97.0%) of lymph node metastasis. Conclusions: CT has high diagnostic value for lymph node metastasis in thoracic esophagel cancer when the lymph node diameter is greater than 1 cm. BLN is the best diagnostic index for lymph node metastasis.