Impact of disagreement between the IMDC and MSKCC risk groups on prognosis in patients with metastatic renal cell carcinoma.

Abstract

556 Background: As the clinical implication of the risk group disagreement between the risk models remains unclear, we aimed 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. Methods: We retrospectively evaluated 176 patients with metastatic renal cell carcinoma (mRCC) who were treated with tyrosine kinase inhibitors as first-line therapy in five 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 MSKCC and IMDC models was evaluated using Cohen’s k coefficient. Oncological outcomes were compared between the agreement and disagreement groups. Results: The number of patients with agreement, upgrade, and downgrade was 135/176 (77%), 39/176 (22%), and 2/176 (1.1%), respectively. Of 41 patients with disagreement, reclassification from the MSKCC-intermediate to the IMDC-poor-risk group was most frequent (n = 34/176, 19%). The Cohen’s k coefficient for agreement of the two risk models was substantial with k value of 0.613 ( P < 0.001). Significantly poorer prognosis was observed in patients with disagreement than in those with agreement. Conclusions: Disagreement between the MSKCC and IMDC models may have a negative impact on prognosis in patients with mRCC. Further study is necessary to validate our findings.