Lymph node metastasis risk factors in clinical stage IA3 lung adenocarcinoma

Lymph node metastasis is a poor prognostic factor for lung cancer. However, the risk of lymph node metastasis has not yet been clarified. This study was conducted to analyze the predictive factors for lymph node metastasis in patients with clinical-stage IA3 lung adenocarcinoma.

We retrospectively analyzed all surgical patients with clinical stage IA3 lung adenocarcinoma admitted to our hospital from January 2017 to January 2022. Three hundred and thirty-four patients underwent lobectomy combined with systematic lymph node dissection. Univariate and multivariate logistic regression analyses were used to predict the risk factors of lymph node metastasis.

Of the 334 patients eligible for this study, the overall lymph node metastasis rate was 15.3%. There were 45 cases with N1 metastasis, 11 cases with N2 metastasis, and five cases with both N1 and N2 metastasis. The lymph node metastasis rate was 18.1% in patients with a consolidation tumor ratio (CTR) of >0.75, 57.9% in those with >5 ng/mL carcinoembryonic antigen (CEA), and 18.0% in those with a maximum standardized uptake value of >5. Receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) for CTR and CEA was 0.790 [95% confidence interval (CI): 0.727-0.853, P < 0.001] and 0.682 (95% CI: 0.591-0.773, P < 0.001), respectively. According to multivariate regression analysis, CEA (>5 ng/mL) [odds ratio (OR) = 3.05, P = 0.016] and CTR (>0.75) (OR = 2.75, P = 0.025) were significantly correlated with lymph node metastasis of clinical stage IA3 lung adenocarcinoma.

CEA (>5 ng/mL) and CTR (>0.75) are two important predictors of lymph node metastasis in patients with clinical stage IA3 lung adenocarcinoma.