American College of Surgeons’ Oncology Group Z0030 found no survival difference between patients with early-stage non-small-cell lung cancer who had mediastinal nodal dissection or systematic sampling. However, a meta-analysis of 1,980 patients in five randomized controlled trials from 1989-2007 associated better survival with nodal dissection. We tested the survival impact of the extent of nodal dissection in curative-intent resections for early-stage non-small cell lung cancer in a population-based observational cohort.
Resections for clinical T1 or T2, N0 or non-hilar N1, M0 non-small-cell lung cancer, within four contiguous United States Hospital Referral Regions from 2009-2019 were categorized into mediastinal nodal dissection, systematic sampling, and neither, based on lymph node stations examined. We compared demographic and clinical characteristics, perioperative complication rates and survival after assessing statistical interactions and confounding.
Of 1,942 eligible patients, 18% had nodal dissection, 6% had systematic sampling, 75% had intraoperative nodal evaluation that met neither standard. In teaching hospitals, nodal dissection was associated with a lower hazard of death than ‘neither’ resections (0.57 [95% confidence interval 0.41, 0.79]) but not systematic sampling (0.74 [0.40, 1.37]) after adjusting for multiple comparisons. There was no significant difference in hazard ratios at non-teaching institutions. Perioperative complication rates were not signficantly worse after mediastinal nodal dissection or systematic sampling, compared to neither.
In teaching institutions, mediastinal nodal dissection was associated with superior survival over less comprehensive pathologic nodal staging. There was no survival difference in non-teaching institutions, a finding which warrants further investigation.

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