Sublobar resection is associated with less lymph nodes examined and lower delivery of adjuvant therapy in patients with 1.5-to 2.0-cm clinical IA2 non-small-cell lung cancer: a retrospective cohort study

OBJECTIVES: CALGB140503, in which nodal sampling was mandated, reported non-inferior disease-free survival for patients undergoing sublobar resection (SLR) compared to lobectomy (L). Outside of trial settings, the adequacy of lymphadenectomy during SLR has been questioned. We sought to evaluate whether SLR is associated with suboptimal lymphadenectomy, differences in pathologic upstaging and survival in patients with 1.5- to 2.0-cm tumours using real-world data.MATERIALS AND METHODS: Using the National Cancer Database(2018-2019), we evaluated patients with 1.5- to 2.0-cm non-small-cell lung cancer who underwent resection (sublobar versus lobectomy). We studied factors associated with nodal upstaging (logistic regression) and survival (Cox regression and Kaplan-Meier method) after propensity matching to adjust for differences among groups.RESULTS: Among 3196 patients included, SLR was performed in 839 (26.3%) (of which 588 were wedge resections) and L was performed in 2357 (73.7%) patients. More patients undergoing SLR (21.7%) compared to L (2.1%) had no lymph nodes sampled (P < 0.001). Those undergoing SLR had fewer total lymph nodes examined (4 vs 11, P < 0.001) and were less likely to have pathologic nodal metastases (4.7% vs 9%, P < 0.001) compared to L. Multivariable analysis identified L [adjusted odds ratio (aOR) 2.21, 95% confidence interval, 1.47-3.35] to be independently associated with pathologic N+ disease. Overall survival was not associated with the type of procedure but was significantly decreased in those with N+ disease.CONCLUSIONS: Despite comparable overall survival to L, SLR is associated with suboptimal lymphadenectomy in patients with 1.5-2.0 cm non-small-cell lung cancer. Surgeons should be careful to perform adequate lymphadenectomy when performing SLR to mitigate nodal under-staging and to identify appropriate patients for systemic therapy.