Construction and validation of a novel prognostic nomogram for patients with sarcomatoid renal cell carcinoma: a SEER-based study

The only one established prognostic nomogram for patients with sarcomatoid renal cell carcinoma (sRCC) was based on a small sample-sized study without external validation, and a nomogram can be applied to western sRCC patients has not yet been developed. Therefore, our study aimed to construct and validate an effective nomogram to predict overall survival (OS) for these patients. The independent predictors for OS were identified and the nomogram was constructed on the basis of a retrospective study of a training cohort consisted of 428 non-Hispanic white sRCC patients registered in the Surveillance, Epidemiology and End Results (SEER) database from January 2010 to December 2015. Then, the discriminative performance of the nomogram was assessed by the concordance index (C-index). OS calibrations of the nomogram were also performed by comparing the nomogram-predicted probability to the observed survival rate. Furthermore, our nomogram was externally validated using two independent cohorts consisted of 71 non-Hispanic black patients and 82 Hispanic patients, respectively. Age at diagnosis, T stage, N stage, bone metastases, liver metastases, lung metastases and nephrectomy were identified as independent predictors for OS. In the training cohort and two validation cohorts, the C-indexes of the nomogram were 0.737, 0.801 and 0.764, respectively. Besides, excellent agreements between the nomogram prediction and the actual observation were achieved in all cohorts. The current study constructed and validated an effective prognostic nomogram for patients with sRCC, which can be used to perform accurate predictions of the 0.5-, 1-, and 2-year possibilities of OS.