Impact of Omission of Intrapulmonary Lymph Node Retrieval on Outcome Evaluation of Lung Cancer Patients Without Lymph Node Metastasis: A Propensity Score Matching Analysis

Abstract

Introduction: Clinical practice of retrieval of segmental (station 13) and subsegmental (station 14) lymph nodes for pathologic examination varies during lung cancer surgery. This study aimed to evaluate whether omitting retrieval of nodes from stations 13 and 14 could affect outcome evaluation for patients with pN0 non-small-cell lung cancer (NSCLC).

Methods: This retrospective study analyzed 442 patients with NSCLC who were treated with both R0 resection and systematic mediastinal lymphadenectomy with pathologically confirmed stage pN0 NSCLC. The study group included patients in whom N1 nodes including stations 10 to 14 were investigated, and the control group included patients in whom stations 10 to 12 only were investigated. Clinical and pathologic parameters of the groups were balanced by propensity score matching, and oncologic outcomes were assessed by the log-rank test.

Results: A total of 435 cases were included in the final analysis (170 in the study group and 265 in the control group). In the study group, a mean ± SD of 5.0 ± 3.0 nodes per case were collected from nodes 13 and 14. After propensity score matching, 143 cases were included in each group. Overall and disease-free survival improved in the study group compared to the control group (P = .027 and P = .021, respectively). T staging and intrapulmonary node collection were prognostic factors for pN0 cases.

Conclusion: Inferior oncologic outcomes of pN0 cases without intrapulmonary node retrieval suggest that the procedure of intrapulmonary lymph node retrieval may play a role in outcome evaluation for pN0 NSCLC patients.

Keywords: Lymph node; NSCLC; Pathologic staging; Prognosis; Segmental; Subsegmental.