Commission on Cancer Standards for Lymph Node Sampling and Oncologic Outcomes After Lung Resection.

Background: The newest Commission on Cancer standards recommend sampling 3 mediastinal and 1 hilar lymph node stations, 3 (N2) 1 (N1), for lung cancer resections. However, the relationship between the Commission on Cancer standards and outcomes has not been thoroughly investigated.

Methods: A prospective institutional database was queried for clinical stage I-III lung resections before the implementation of the new standards. The relationship between the 3 (N2) 1 (N1) standard ("guideline concordant") and outcomes (upstaging, complications, receipt of adjuvant therapy, locoregional/distant recurrence, and survival) was assessed with multivariable models and stratified by stage.

Results: Of 9289 pulmonary resections, 3048 (33%) were guideline concordant and 6241 (67%) were not. Compared with nonconcordant, those that were guideline concordant had higher rates of nodal upstaging (21% vs 13%; odds ratio [OR], 1.32 [95% CI, 1.14-1.51]; P < .001) and in-hospital complications (34% vs 27%; OR, 1.17 [95% CI, 1.05-1.30]; P = .004) but similar adjuvant systemic therapy administration (19% vs 13%; OR, 1.09 [95% CI, 0.95-1.24]; P = .2; 98% chemotherapy). Locoregional and distant recurrences were not significantly improved with guideline concordance across clinical stage I, II, and III subsets. Overall survival was similar in clinical stages I and II, but improved survival was observed for guideline concordant clinical stage III patients (hazard ratio, 0.85 [95% CI, 0.74-0.97]; P = .02).

Conclusions: Sampling 3 (N2) 1 (N1) was associated with increased upstaging and complications but not with decreased recurrence or mortality in clinical stage I or II patients. Survival was improved for concordant, clinical stage III patients. Further study is indicated to determine the ideal lymph node sampling strategy across heterogeneous lung cancer patients.