Risk Prediction of Multiple-station N2 Metastasis in Patients with Upfront Surgery for Clinical Single-station N2 Non-Small Cell Lung Cancer

Abstract Objectives To investigate long-term outcomes and develop a risk model for pathological multi–station N2 (pN2b) in patients who underwent upfront surgery for clinical single–station N2 (cN2a) non–small cell lung cancer (NSCLC). Methods From 2006 to 2018, 547 patients who had upfront surgery for suspected cN2a NSCLC underwent analysis. A risk model for predicting pN2b metastasis was developed using preoperative clinical variables via multivariable logistic analysis. Results Among 547 clinical cN2a NSCLC patients, 118 (21.6%), 58 (10.6%), and 371 (67.8%) had pN0, pN1, and pN2. Among 371 pN2 NSCLC patients, 77 (20.8%), 165 (44.5%), and 129 (34.7%) had pN2a1, pN2a2, and pN2b. The 5-year overall survival rates for pN2a1 and pN2a2 were significantly higher than for pN2b (p = 0.041). Histologic type (p < 0.001), age ≤ 50 years (p < 0.001), preoperatively confirmed N2 metastasis (p < 0.001), and clinical stage IIIB (vs. IIIA) (p = 0.003) were independent risk factors for pN2b metastasis. The risk scoring system based on this model demonstrated good discriminant ability for pN2b disease (area under receiver operating characteristic: 0.779). Conclusions In cN2a NSCLC patients, those with multiple N2 metastases indicate worse prognosis than those with a single N2 metastasis. Our risk scoring system effectively predicts pN2b in these patients.