Occult Node Detection With Lobectomy Versus Segmentectomy for Stage IA NSCLC

Besides the discussion on parenchymal margin, data on the extent of lymph node (LN) dissection are scarce, especially in segmentectomy. This study aimed to investigate the extent of LN dissection and detection of occult disease in segmentectomy compared with lobar resection.

We performed a single-institution, retrospective analysis for patients who underwent segmentectomy or lobectomy for clinical T1N0M0 (≤3 cm) NSCLC from 2012 to 2022. The extent of LN dissection and the rate of detection of occult LN disease were compared. N1 nodes were further classified as collected as a specimen during the operation (N1 dissection) and the nodes retrieved from lung specimens by pathologists (N1 lung specimen).

During the study period, 957 lobectomies and 402 segmentectomies were performed for clinical T1N0M0 NSCLC. The median number of sampled LNs was significantly higher in the lobectomy group (18 versus 12; p < 0.001). This tendency was similar across all node groups, including N2 nodes (7 versus 5), N1 dissection nodes (6 versus 4), and most significantly N1 lung specimen nodes (4 versus 0; all p < 0.001) There was a significant difference in N1 occult nodes (13.3% versus 3.7%; p < 0.001), whereas the difference was not significant in N2 occult nodes (5.5% versus 3.2%; p = 0.074).

Segmentectomy was associated with less LN sampling, which translated into lower detection of occult nodal metastasis in N1 LNs. Although standardized pathologic dissection could potentially improve detection, there is likely an inevitable inferiority in LN sampling with segmentectomy.