BACKGROUNDTo explore predictors of mediastinal and intrapulmonary pathologic lymph node involvement in clinical stage I non-small cell lung cancer.

METHODSFrom July 1999 to April 2001, 159 patients with clinical stage I non-small cell lung cancer underwent lobectomy and complete mediastinal or intrapulmonary lymph node dissection. All the resected lymph nodes were pathologically analyzed to find out pathologic involvement. Univariate and multivariate analyses were used to clarify predictors of lymph node metastasis.

RESULTSOf all 159 patients, 37 (23%) had pathologic lymph node metastasis. According to logistic regression analysis, tumor size, grade of cell differentiation, and pleural invasion were the significant predictors of lymphatic metastasis ( P=0.003, P=0.004, P =0.005). Patients with 2 or more factors were more liable to have lymph node metastasis than those with less than 2 factors ( P < 0.001).

CONCLUSIONSWhen patients with clinical stage I non-small cell lung cancer have such clinical factors as tumor diameter > 2.0 cm, moderate or poor differentiation, or pleural invasion, they will be more liable to have lymph node metastasis. Therefore, it should be more prudent to select therapeutic way and judge their prognosis.