Risk prediction of multiple-station N2 metastasis in patients with upfront surgery for clinical single-station N2 non-small cell lung cancer

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). 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. 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). 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.