Abstract: Objective The aim of this study was to investigate the risk factors of lymph node metastasis in early lung adenocarcinoma,and then determine the surgical indications for lymph node dissection in early lung adenocarcinoma.Methods In this study,a total of 301 patients with lung adenocarcinoma who underwent radical resection for lung cancer and whose tumor diameter was less than or equal to 30 mm were selected for surgical treatment at Harbin Medical University Cancer Hospital in 2018.The clinical data were retrospectively analyzed,and logistic regression was applied.The independent risk factors of lymph node metastasis were analyzed,and the ROC curve was drawn to evaluate the effect of predicting lymph node metastasis.Results The study included 301 patients,of whom 19(6.3%)had lymph node metastasis.The ratio of tumor solid component diameter to tumor diameter(C/T)(P=0.003)and the preoperative serum level of carcinoembryonic antigen(CEA)(P=0.024)were independent risk factors for lymph node metastasis in patients with early lung adenocarcinoma.The ROC curve showed the C/T ratio(AUC=0.791,P＜0.001),serum CEA(AUC=0.681,P=0.008),and the combination of C/T ratio with serum CEA(ACU=0.841,P＜0.001),which was good the prediction effect on lymph node metastasis in patients with early lung adenocarcinoma.Conclusion For early lung adenocarcinoma with tumor diameter ≤30 mm,combined serum CEA with C/T ratio,serum CEA alone,and C/T ratio alone may become clinical indicators to guide lymph node dissection.

Key words: Lung adenocarcinoma, Lymph node metastasis, C/T ratio, CEA