Risk-adapted nodal evaluation in stage IA non-small cell lung cancer: a population-based competing-risk analysis

The oncologic value of intensified lymph node (LN) evaluation in stage IA non-small cell lung cancer (NSCLC) remains uncertain in the era of surgical de-escalation. Although expanded nodal assessment may reduce understaging, whether it is associated with meaningful survival differences in this favorable-risk population is unclear. Clarifying this issue is essential to balance oncologic adequacy and surgical burden.

We conducted a population-based cohort study using the Surveillance, Epidemiology, and End Results database and included patients with surgically treated pathologic stage IA (T1N0M0) NSCLC. The extent of nodal evaluation was quantified by the number of examined lymph nodes. Propensity score matching was used to balance baseline characteristics. Cancer-specific and other-cause death were analyzed using cumulative incidence functions and Fine-Gray competing-risk models. Prespecified subgroup analyses assessed heterogeneity of association, particularly according to tumor size.

We included 24,215 patients, with 13,812 after matching. Intensified nodal evaluation, defined as ≥ 6 examined lymph nodes (ELNs), was associated with lower cancer-specific mortality (5-year cumulative incidence, 12.9% vs. 15.3%; absolute risk reduction [ARR] 2.4%; Gray's P < 0.001). In multivariable Fine-Gray analysis, ELNs ≥ 6 remained independently associated with lower cancer-specific mortality (subdistribution hazard ratio 0.78, 95% CI 0.74-0.83). The association was minimal in tumors ≤ 1 cm but more evident in tumors > 1 cm. Sensitivity analyses using ELNs ≥ 10 yielded similar findings.

The association between intensified nodal evaluation and lower cancer-specific mortality in stage IA NSCLC varies by tumor size. This association was more evident in tumors > 1 cm, supporting further investigation of a size-based, risk-adapted approach to surgical staging in early-stage NSCLC.