Background: This study aims to identify the predictors of lymph node metastasis in patients with T1aN0M0 adenocarcinoma of the lung.

Methods: In this retrospective study, a total of 364 patients (170 males, 194 females; mean age 60.8±8.4 years; range: 33 to 82 years) with clinical stage T1aN0M0 pulmonary adenocarcinoma who were treated between January 2011 and October 2015 were included. Medical records were analyzed and relevant clinical data and pathological results were recorded. Univariate and multivariate analyses were performed to identify the predictors of lymph node metastasis.

Results: Multivariate analysis demonstrated that groundglass opacity, high serum carcinoembryonic antigen concentrations (>5 ng/mL), and pathogenic type were the predictors of lymph node metastasis in T1a pulmonary adenocarcinoma. For solid nodules, tumor diameter, air bronchogram, and high serum carcinoembryonic antigen concentrations were the predictors of lymph node metastasis.

Conclusion: Lymph node metastasis cannot be found in patients with clinical stage T1aN0M0 pulmonary adenocarcinoma presenting as a pure ground-glass opacity or mixed tumor with solid component of diameter <5 mm. However, systematic lymphadenectomy is indicated in all patients with pure solid nodules and those with mixed nodules with solid component ≥5 mm diameter, particularly those with serum carcinoembryonic antigen concentrations higher than 5 ng/mL.

Keywords : Cancer; clinical stage; lymph node; non-small cell lung cancer; pulmonary adenocarcinoma