Impact of Disagreement Between Two Risk Group Models on Prognosis in Patients With Metastatic Renal-Cell Carcinoma

Purpose: To investigate the impact of the risk group disagreement between the Memorial Sloan Kettering Cancer Center (MSKCC) and the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) models on prognosis. Patients and Methods: We retrospectively evaluated 176 patients with metastatic renal-cell carcinoma who were treated with tyrosine kinase inhibitors as first-line therapy in 5 hospitals between October 2008 and August 2018. The risk group classification differences between the MSKCC and the IMDC models were evaluated using criteria of agreement (identical risk group in both the MSKCC and IMDC models) and disagreement (not identical risk group in both the MSKCC and IMDC models). The agreement of risk stratification between the models was evaluated using the Cohen κ coefficient. Oncologic outcomes were compared between the agreement and disagreement groups. Results: The number of patients with agreement, upgrade, and downgrade was 135 (77%), 39 (22%), and 2 (1.1%), respectively. Of 41 patients with disagreement, reclassification from the MSKCC-intermediate to the IMDC-poor risk group was most frequent (n = 34, 19%). The Cohen κ coefficient for agreement was substantial, with κ = 0.613 (P <.001). Significantly poorer prognosis was observed in patients with disagreement than in those with agreement. Neutrophil count, hemoglobin, serum calcium concentration, and C-reactive protein were significantly different between the groups. Conclusion: Disagreement between the MSKCC and IMDC models may have a negative impact on prognosis in patients with metastatic renal-cell carcinoma. The inclusion of systematic inflammation markers in a risk model may be essential for prognosis prediction.