Contralateral mediastinal lymph node micrometastases assessed by video-assisted thoracoscopic surgery in stage I non-small cell left lung cancer.

Objectives: Survival of patients with left-sided stage I non-small cell lung cancer (NSCLC) is unsatisfactory, probably because of the high incidence of contralateral mediastinal node involvement. In this study, occult micrometastases to the right upper mediastinal nodes were retrospectively investigated in patients with left-sided stage I NSCLC.
Methods: Nineteen patients with clinical stage I NSCLC underwent video-assisted thoracoscopic lobectomy and bilateral mediastinal node dissection (BMD). Clinical data and survival of patients with BMD were compared with those of 25 left-unilateral mediastinal node dissection (UMD) patients. Occult micrometastases were detected using the cytokeratin 19 mRNA reverse transcription-polymerase chain reaction method.
Results: Pathological N2 disease was found in 1 patient, and 18 had pN0 disease. The operative time, blood loss, duration of chest tube drainage and duration of postoperative hospital stay were not different between BMD and UMD patients. Nodal micrometastases were detected in 11/19 (57.8%) patients. Skip micrometastases to the level N3 nodes without N1 and N2 node involvement were observed in 8/11 (72.7%) patients. Patients with BMD are all alive and have had no recurrence during the median follow-up period of 21.4 months. Overall 3-year survival and disease-free 3-year survival were not significantly different between the two groups.
Conclusion: In this preliminary study, occult micrometastases to the level N3 nodes occurred frequently in patients with left-sided clinical N0 stage I NSCLC. Postoperative survival of patients with occult micrometastases to the level N3 node does not appear to be poor. Further follow-up and work are needed.