Development and validation of a nomogram prognostic model for small cell lung cancer optimized by age and metastatic pattern

Abstract

Background: The objective of this study is to establish and validate a novel nomogram by optimizing the eighth edition of the TNM classification by adding age and metastatic pattern. Methods: Clinical data of 1085 patients with small cell lung cancer (SCLC) from a Chinese multi-institutional registry were subjected to bootstrap external validation based on a prognostic nomogram built by integrating significant prognostic factors for survival from 21,707 cases from the Surveillance, Epidemiology, and End Results (SEER) database (training cohort). Kaplan–Meier survival analyses and concordance index (c-index) were used to test the application of the risk stratification system. Results: Both cohorts exhibited significant mortality increases with age (SEER hazard ratio [HR], 1.319; China HR, 1.237; both P < 0.001). The patterns of organ metastasis, liver (HR = 3.219), lung (HR = 1.750), brain (HR = 1.509), and bone (HR = 2.614), had significantly disparate prognoses. The nomogram based on the TNM classification of lung cancer was optimized by age and organ metastatic pattern, with an improvement in the C-index (from 0.617 to 0.661 in the training cohort and from 0.620 to 0.668 in the external validation cohort). Conclusion: This model provides useful quantitative tool for physicians to make critical diagnostic and treatment decisions for patients with SCLC.