Abstract Background Surgical resection followed by adjuvant chemotherapy is currently the first choice for the treatment of clinical N1 (cN1) non-small cell lung cancer (NSCLC). However, diagnosing cN1 correctly can be difficult, even with current imaging diagnostic technologies. We aimed to analyze the diagnostic accuracy of preoperative nodal status and the predictive factors for nodal upstaging of cN1-NSCLC. Methods Patients receiving surgery for cN1-NSCLC in 2010 (n = 1040) were enrolled in the Japanese Joint Committee of Lung Cancer Registry Database. We investigated the diagnostic accuracy of cN1, predictive factors for nodal upstaging, and prognostic factors for overall survival (OS) and recurrence-free survival (RFS). Results The 5-year OS and RFS for all patients were 58.2% and 42.7%, respectively. The postoperative pathological nodal status included N0 (36.6%), N1 (39.7%), N2 (23.6%), and N3 (0.1%). In multivariate analysis, younger age (P = .005), no history of smoking (P = .006), and adenocarcinoma (P &amp;lt; .001) were significant predictive factors for nodal upstaging. Older age (P &amp;lt; .001) and higher clinical T (cT) factor (P &amp;lt; .001) were significant indicators for worse OS, while older age (P = .02), higher cT factor (P = .019), high carcinoembryonic antigen value (P = .002), and adenocarcinoma (P = .008) were significant indicators for worse RFS. Conclusions The diagnostic accuracy of cN1 in this study was ~40%. No history of smoking and adenocarcinoma were significant predictors for nodal upstaging. Although younger age was a significant predictor for nodal upstaging, it was a significant factor for better prognosis.

Predictors of nodal upstaging in clinical N1 nonsmall cell lung cancer