Development and validation of nomograms for predicting overall and cancer-specific survival in young patients with non-small cell lung cancer

BACKGROUND: Young patients with non-small cell lung cancer (NSCLC) represent a distinct subgroup of patients with this disease. This study aimed to construct nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) of young patients with NSCLC. METHODS: NSCLC patients under 50 years old diagnosed between 2010 and 2016 were selected from the Surveillance, Epidemiology, and End Results (SEER) database and randomly divided into training (n=1,357) and validation (n=678) cohorts at a ratio of 2:1. Independent prognostic factors for OS or CSS were identified through the log-rank test, Cox proportional hazards models or competing risk model and further integrated to construct nomograms. The predictive capability of the nomogram was assessed by Harrell’s concordance index (C-index), the calibration curve and risk group stratification. RESULTS: A total of 2,035 patients were enrolled. In the training cohort, insurance, marital status, histological type, grade, T stage, N stage and surgery were identified as independent prognostic for OS and CSS. The C-index value were 0.759 [95% confidence interval (CI): 0.731–0.787] for OS and 0.810 (95% CI: 0.803–0.818) for BCSS in the training cohort and 0.751 (95% CI: 0.711–0.790) for OS and 0.807 (95% CI: 0.795–0.819) for CSS in the validation cohort. The calibration curves showed optimal agreement between the predicted and actual survival both in internal and external validation. In addition, patients in the validation cohort within different risk groups exhibited significantly different survival even in each TNM stage. CONCLUSIONS: Nomograms were developed and validated to predict OS and CSS of young patients with NSCLC in our study. A prospective study with more potential prognostic factors and the latest TNM classification is required to ameliorate this model.