Lymph node metastasis in clinical stage IA peripheral lung cancer.

Objectives: To investigate lymph node metastasis especially the intrapulmonary node in clinical IA peripheral lung cancer patients to evaluate the indications for lung segmentectomy in lymph node level.

Materials And Methods: Patients (n=292) with clinical stage IA peripheral lung cancer received radical lobectomy at our department between October 2013 and July 2014 were enrolled in our study. Lymph nodes were obtained during routine surgical procedures while segmental lymph nodes were dissected from the resected lobe for pathological examination. New classification for pulmonary adenocarcinoma with each histologic component was also analyzed.

Results: The percentage of patients found to have no lymph node metastasis was 90.4% (264/292). Tumor size on computed tomography and tumor consistency were independent predictors for lymph node metastasis. Tumor with a dominant ground-glass opacity (GGO) component was a good predictor for lymph node metastasis (p<0.001). Metastasis was more common in larger tumors (p<0.001), but there was non-tumor bearing segment metastasis even in tumor less than 1cm. Patients with micropapillary or solid component were correlated with lymph node metastasis (p=0.001 and p=0.009, respectively).

Conclusions: The rate of metastasis to the lymph nodes is very low in clinical stage IA peripheral lung cancer patients. Patients with a dominant GGO component on CT might be the suitable candidates for lung segmentectomy because of almost no lymph node metastasis. Careful selection should be made for the patients with tumor size ≤2 cm who had metastasized nodes in non-tumor bearing segment when considering segmentectomy. If the resected tumor had micropapillary or solid component, the lobectomy might be considered.