Novel risk stratification criteria of metastatic renal cell carcinoma (mRCC) patients (pts) treated with immune checkpoint inhibitors (ICI).

Abstract

e16068 Background: IMDC risk criteria is the gold standard for predicting outcomes for mRCC pts. We developed novel risk groups for mRCC pts treated with ICI. Methods: We performed a retrospective review of 100 ICI-treated mRCC pts at Winship Cancer Institute from 2015-2018. Overall survival (OS) and progression-free survival (PFS) were used to measure outcomes; OS was the primary outcome. We obtained baseline monocyte-to-lymphocyte ratio (MLR), body mass index (BMI), and metastatic (met) sites. We created a new variable (D_met) that combines number and sites of met: 0 = < 2 met sites; 1 = ≥ 2 met sites without liver metastases (mets); 2 = ≥ 2 met sites with liver mets. Cox proportional hazard model and Kaplan-Meier method were used for association with OS and PFS. Recursive partitioning and regression tree analyses were used for risk stratification. Discrimination of the risk score was measured by Uno C-statistics. Results: The pts were 66% males, 78% clear cell RCC (ccRCC), and 71% received anti-PD-1 monotherapy. Very poor risk pts (MLR ≥ 0.93 or MLR < 0.93, BMI < 24, and D_Met = 2) had significantly shorter OS and PFS than good risk pts (MLR < 0.93, BMI ≥ 24, and D_Met = 0) in univariable and multivariable analysis (UVA and MVA, Table). The Uno C-statistic for our risk grouping criteria compared to IMDC is 0.687 vs 0.566 (p = 0.061) for OS and 0.594 vs 0.541 (p = 0.78) for PFS. Conclusions: Risk grouping using MLR, BMI, and number and sites of mets may predict survival in mRCC pts treated with ICI. These results should be validated in a larger, prospective study. [Table: see text]