Clinical stage-specific prognostic impact of adequate lymphadenectomy in early-stage lung cancer.

Objectives: To assess the prognostic impact of adequate lymphadenectomy and determine the optimal nodal assessment for different clinical stages of lung cancer.

Methods: We retrospectively reviewed 1214 patients with clinical stage I-III non-small cell lung cancer who had preoperative PET/CT and curative surgery (2006-2017). Patients were categorized based on whether they had adequate [R0] or inadequate lymphadenectomy [R(un)]. Propensity score matching was conducted to minimize bias. Primary end-points were recurrence-free survival (RFS), overall survival (OS), and cancer-specific survival (CSS). Secondary end-points included outcomes stratified by clinical stages.

Results: Multivariate Cox analysis identified preoperative carcinoembryonic antigen level, tumour size, uptake of tumour on PET/CT, R(un) (Hazard ratio (HR)= 2.16; p < 0.001), angiolymphatic invasion, lymph node involvement, and postoperative adjuvant therapy as independent predictors of RFS. The matched cohort included 440 R0 and 440 R(un) patients, with a median follow-up of 94 months. Significant differences were found in 10-year RFS (77.2% vs 61.3%, p < 0.001), OS (75.8% vs 64.3%, p < 0.001) and CSS (83.8% vs 74.2%, p < 0.001). Despite longer operative time for R0 (210 vs 195 min, p = 0.008), perioperative complications, hospital stay length, and blood loss were similar. Subgroup analysis showed R(un) as an independent predictor of RFS in clinical stages IA3 (HR = 2.53, p = 0.001), IB (HR = 1.71, p = 0.046), and II (HR = 2.44, p < 0.001), but not in IA1 or IA2. R0 had significantly better RFS than R(un) in matched cohort of stages IA3 (p = 0.003), IB (p = 0.001), and II (p = 0.001).

Conclusions: Adequate lymph node assessment improves prognosis in patients with clinical stages ≥ IA3. A uniform nodal assessment approach should be reconsidered for different clinical stages.