Objective  To investigate the relationship between lymph node metastasis of lung adenocarcinoma and relative factors.

  Methods  A total of 1 085 patients diagnosed with invasive lung adenocarcinoma were enrolled. The relationship between lymph node metastasis and relative factors, including age, sex, adenocarcinoma subtype, tumor location, tumor size and pleural invasion, was analyzed statistically. The relative factors were selected using a chi-square test for univariate analysis. Statistically significant prognostic factors were analyzed using a Logistic regression model. Based on this model, a nomogram was developed and evaluated using Harrell's concordance index (Cindex), calibration plots and a receiver operating characteristic curve (ROC).

  Results  The results of multivariate unconditional Logistic regression analysis showed that age ≤67 years (OR=1.599, P=0.036), adenocarcinoma subtype (OR=1.337, P < 0.001), tumor location (OR= 1.162, P=0.027), tumor size (OR=1.765, P < 0.001) and pleural invasion (OR=2.179, P < 0.001) were independent risk factors for lymph node metastasis of lung adenocarcinoma. These factors were incorporated to construct a nomogram. Its C-index was 0.860 (95%CI: 0.834-0.885). The calibration curve showed excellent agreement between the predicted and observed risks of lymph node metastasis of lung adenocarcinoma. The area under the curve (AUC) of the ROC curve was 0.829 (95%CI: 0.799-0.858).

  Conclusions  Age, adenocarcinoma subtype, tumor location, tumor size and pleural invasion were independent risk factors, significant for predicting lymph node metastasis of lung adenocarcinoma. A nomogram was constructed and validated to have a good predictive ability.