Application of the International Metastatic Renal Cell Carcinoma Database Consortium and Memorial Sloan Kettering Cancer Center Risk Models in Patients with Metastatic Non-Clear Cell Renal Cell Carcinoma: A Multi-Institutional Retrospective Study Using the Korean Metastatic Renal Cell Carcinoma Registry

PURPOSE: The International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) and the Memorial Sloan Kettering Cancer Center (MSKCC) risk models were developed predominantly with clear cell renal cell carcinoma (RCC). Accordingly, whether these two models could be applied to metastatic non-clear cell RCC (mNCCRCC) as well has not been well-known and was investigated herein. Materials and Methods: From the Korean metastatic RCC registry, a total of 156 patients (8.1%) with mNCCRCC among the entire cohort of 1,922 patients were analyzed. Both models were applied to predict first-line progression-free survival (PFS), total PFS, and cancer-specific survival (CSS). RESULTS: The median first-line PFS, total PFS, and CSS were 5, 6, and 24 months, respectively. The IMDC risk model reliably discriminated three risk groups to predict survival: the median firstline PFS, total PFS, and CSS for the favorable, intermediate, and poor risk groups were 9, 5, and, 2 months (p=0.001); 14, 7, and 2 months (p < 0.001); and 41, 21, and 8 months (p < 0.001), all respectively. The MSKCC risk model also reliably differentiated three risk groups: 9, 5, and, 2 months (p=0.005); 10, 7, and 3 months (p=0.002); and 50, 21, and 8 months (p < 0.001), also all respectively. The concordance indices were 0.632 with the IMDC model and 0.643 with the MSKCC model for first-line PFS: 0.748 and 0.655 for CSS. CONCLUSION: The current IMDC and MSKCC risk models reliably predict first-line PFS, total PFS, and CSS in mNCCRCC.