A Novel Nomogram Predicting the Overall Survival of Patients with Metastatic Non-clear Cell Renal Cell Carcinoma: A Large Population-Based Investigation

Objective: Metastatic non–clear cell renal cell carcinoma (non-ccmRCC) is the end stage of this disease with a poor prognosis. This study aimed to investigate prognostic clinicopathological factors and develop nomogram models for non-ccmRCC patients using a large population-based cancer database. Methods and materials: Data of all patients with non-ccmRCC from 2010 to 2015 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database and analyzed retrospectively. Cox regression models were used to analyze prognostic risk factors for overall survival (OS). Prognostic nomogram was carried out with R software to predict the OS probability. The validation of the nomogram was performed using calibration curves and receiving operating characteristic (ROC) curve. Results: A total of 776 non-ccmRCC patients in the SEER database were included. We separated non-ccmRCC patients into three groups (group 1: one, group 2: two, group 3: three or more) according to the number of metastatic organs. Age, histology, T stage, N stage, number of metastatic organs, surgery, and chemotherapy were independent risk factors, and hence integrated into the models. The calibration curves for 6-, 12-, and 18-month OS suggested perfect agreement between the prediction by nomogram and the actual survival outcome. The 6-, 12-, and 18-month AUC of the nomogram based on the time-dependent ROC curve analysis were 0.784, 0.754, and 0.766, respectively. The result demonstrated the promising prognostic value of the nomogram. Conclusions: We performed the first accurate nomogram for OS prediction of non-ccmRCC patients, which might help clinicians in treatment decision making.