The impact of dissection of station 9 on survival and the necessity of pulmonary ligament division during upper lobectomy for lung cancer.

Background We conducted this study to investigate the need for dissection of station 9 lymph nodes during upper lobectomy for non-small-cell lung cancer (NSCLC) and to find out the operative results of inferior pulmonary ligament division. Methods A total of 840 patients who underwent upper lobectomy for NSCLC between January 2007 and June 2020 were evaluated retrospectively. The patients were separated into two groups - those having undergone lymph node dissection of station 9 and inferior pulmonary ligament dissection (Group I) and those who did not (Group II). In these groups, the prognostic value of station 9 lymph nodes and postoperative effects (drainage time, prolonged air leak, dead space and length of hospital stay) of ligament division or preservation were analyzed. Results The number of patients with station 9 lymph node metastasis was only one (0.1%) and that was multi-station pN2 disease. Station 9 lymph nodes were found in 675 (80.4%) patients, while 22 (2.6%) patients had no lymph nodes in the dissected material. In the other 143 (17%) patients, the inferior pulmonary ligament and station 9 were not dissected. While 5-year survival was 64.9% in 697 patients of Group I, it was 61.3% in 143 patients of Group II (p = 0.56). There was no statistically significant difference between the groups in postoperative effects of ligament division or preservation. Conclusions In upper lobectomies, status of station 9 does not have a significant impact on patients' survival and lymph node staging. Additionally, preservation or division of the inferior pulmonary ligament has no significant advantage or disadvantage.