Lobectomy does not confer survival advantage over segmentectomy for non-small cell lung cancer with unsuspected nodal disease

Objective: Conversion to lobectomy is typically performed when positive lymph nodes are found during intentional segmentectomy. Our objective was to evaluate survival after lobectomy and segmentectomy in patients with unsuspected nodal metastases. Methods: The National Cancer Database was queried for patients with clinical T1N0, pathological N1/N2 non-small cell lung cancer (NSCLC) who underwent either lobectomy or segmentectomy. Survival differences between the 2 groups were evaluated using a propensity score model. Cox regression analysis was used to evaluate predictors of overall survival, including adjuvant treatment. Statistical analysis was done using SPSS version 21.0 (IBM Corp, Armonk, NY). Results: Between 2004 and 2015, unsuspected pathological N1 disease for clinical T1N0M0 NSCLC was found in 2.5%(228/9118) and 6.7%(8915/132,604) of patients who underwent segmentectomy and lobectomy, respectively. The incidence of unsuspected pathological N2 disease for clinical T1N0M0 NSCLC was 2.4%(224/9118) after segmentectomy and 3.9% (5192/132,604) after lobectomy. Using propensity matched pairs (227 pairs for N1 and 215 for N2), segmentectomy showed equivalent 5-year survival compared with lobectomy for the N1 group (41.9% vs 44.3%; P = .35), and N2 group (41.6% vs 37.2%; P = .99). In a multivariable model, adjuvant chemotherapy was associated with better survival of patients with unsuspected N1 (hazard ratio, 0.613; 95% confidence interval, 0.536-0.700; P<.001) and N2 (hazard ratio, 0.684; 95% confidence interval, 0.583-0.802; P<.001) nodal metastases. Conclusions: Survival is similar between lobectomy and segmentectomy for clinical T1N0 and unsuspected pathological N1/N2 nodal metastases. The use of adjuvant chemotherapy significantly improves survival in patients with lymph node metastasis (N1/N2) independent of the type of anatomic lung resection.