A nomogram to predict prognosis of small-cell lung cancer patients in stage II based on the ninth edition of the tumor-node-metastasis staging system.

BACKGROUND: Existing prognostic models for small-cell lung cancer (SCLC) are based on previous versions of tumor-node-metastasis (TNM) staging. Therefore, this study was devoted to developing a nomogram based on the 9th TNM staging to predict the prognosis of stage II SCLC patients. This nomogram aims not only to provide a more accurate prognostic prediction for clinicians but also to assist in personalized treatment decision - making for stage II SCLC patients, which is of great significance in improving the overall survival rate and quality of life of patients. METHODS: This retrospective study collected 1250 patients diagnosed with stage II SCLC between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. We used nomograms based on Cox proportional hazards analysis and the Kaplan Meier method to conduct the survival analysis of the selected patients. Moreover, the consistency index (C-index) was used to compare the predictive ability of nomograms based on the 8th or 9th edition TNM classification. RESULTS: In light of Cox regression analysis, we respectively took six independent factors into the nomogram of classifications of two editions, including age, the kind of surgery, radiotherapy, chemotherapy, differentiation and time to treatment. The C-indices were 0.664 (SE = 0.009) and 0.666 (SE = 0.009) in nomograms based on the 8th and 9th TNM staging, respectively. CONCLUSIONS: The predictive ability of the nomogram based on the 8th and 9th TNM staging was comparable. In addition, through our validation, the 9th edition of TNM staging system for SCLC has a slight advantage over the 8th edition.