Abstract 216P
Background
The prognostic significance of skip metastasis, defined as N2 lymph node involvement without N1 lymph node metastasis, in non-small cell lung cancer (NSCLC) remains controversial, particularly in the context of the recently revised N2a (single-station) and N2b (multistation) subcategories. This study investigates the survival impact of skip metastasis in these subgroups to refine the stratification of N2 disease and inform TNM staging revisions.
Methods
We retrospectively analyzed 1,873 NSCLC patients who underwent surgery with systematic lymph node dissection at a single institution. Patients were categorized into pN1, skip pN2a, non-skip pN2a, skip pN2b, and non-skip pN2b groups. Overall survival (OS) and disease-free survival (DFS) were assessed using Kaplan-Meier analysis and Cox proportional hazards regression, with propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) applied to minimize confounding.
Results
Skip metastasis was identified in 34.1% of pN2 cases, with a higher incidence in pN2a (41.3%) than in pN2b (24.3%). Skip pN2a showed significantly better 5-year OS and DFS rates compared to non-skip pN2a (72% vs. 67%, p=0.022; 57% vs. 48%, p=0.002). Similarly, skip pN2b had superior outcomes compared to non-skip pN2b (5-year OS: 65% vs. 58%, p=0.008; DFS: 42% vs. 37%, p=0.034). Notably, no significant survival difference was observed between skip pN2a and pN1, or between non-skip pN2a and skip pN2b, even after PSM and IPTW adjustments.
Conclusions
Skip metastasis confers a survival advantage in both pN2a and pN2b NSCLC subgroups, emphasizing its independent prognostic value. Furthermore, the comparable survival between skip pN2a and pN1, as well as between non-skip pN2a and skip pN2b. These findings highlight the need for precise nodal assessment to optimize prognostic accuracy and guide personalized therapeutic strategies in NSCLC.
Legal entity responsible for the study
S. Liang.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.