Required area of lymph node sampling during segmentectomy for clinical stage IA non–small cell lung cancer

ObjectiveTo investigate the required area of lymph node sampling during segmentectomy, especially for segmental nodes at the nonresected segments, we examined the distribution of sentinel nodes in patients with non–small cell lung cancer who underwent segmentectomy.MethodsNinety-four patients with clinical T1 N0 M0 non–small cell lung cancer were treated by using segmentectomy and dissection of lymph nodes with sentinel node identification using 99mTc-phytate. Anatomic locations of the segments were classified as either anterior or posterior, and correlations of anatomic location with the distribution of sentinel nodes at the segmental nodes were then examined.ResultsOf the 94 patients, segmental nodes at both the resected and nonresected segments could be dissected in 42 patients. Segmental sentinel nodes were found at the resected segments in 27 (64%) of these 42 patients, a frequency that was significantly higher than that (12/42 [29%]) seen at the nonresected segments (P = .001). Seven (47%) of the 15 patients with tumors in the anteriorly located segments had segmental sentinel nodes at the nonresected segments, a frequency that was significantly higher than that (4/24 [17%]) seen in patients with tumors in the posteriorly located segments (P = .04).ConclusionThe lymphatic flow from the anteriorly located segment can frequently go directly to the segmental lymph nodes of the posteriorly located segment, probably because the lobar bronchi locate at the posterior side in the thorax. Therefore segmental lymph nodes should be dissected at both the resected and nonresected segments during segmentectomy, especially for tumors in the anteriorly located segment.