A novel nomogram to identify the III-N2 non-small cell lung cancer patients who may benefit from adjuvant radiotherapy

Purpose: We aimed to develop a novel risk stratification system based on a prognostic nomogram to identify patients with pIII-N2 non-small cell lung cancer (NSCLC) who may benefit from postoperative radiotherapy (PORT) after complete resection. Methods We retrospectively enrolled 3,520 eligible NSCLC patients with pIII-N2 stage disease from the Surveillance, Epidemiology, and End Results database. Stabilized inverse probability of treatment weighting (sIPTW) was used to equilibrate the characteristic baseline to reduce bias. We established a risk stratification tool using a nomogram that incorporated independent factors identified using least absolute shrinkage and selection operator (LASSO) Cox regression. Kaplan–Meier and subgroup survival analyses were conducted to estimate the benefit of PORT in every risk stratification. Results Kaplan–Meier survival analysis observed that high-risk patients owned a significant improvement in overall survival (OS) after PORT ( p  = 0.002), while those in low- or intermediate-risk cohorts did not show such improvement. Subgroup survival analysis suggested that patients with a high lymph node ratio ≥ 0.56 (hazard ratio [HR] = 0.803; 95% confidence interval [CI]:0.661–0.975, p  = 0.027), without postoperative chemotherapy (HR = 0.782; 95% CI: 0.619–0.989; p  = 0.040), and those in the high-risk group (HR = 0.577; 95% CI: 0.410–0.812; p  = 0.001) achieved a significant OS advantage from PORT. Conclusion This novel risk stratification system based on nomogram provides a preliminary identification of potential pIII-N2 NSCLC patients who are more likely to benefit from PORT.