Novel risk scoring system for metastatic renal cell carcinoma (mRCC) patients (pts) treated with cabozantinib (C).

Abstract

734 Background: Cabozantinib (C) is an effective treatment for metastatic renal cell carcinoma (mRCC) patients (pts). The international mRCC database consortium (IMDC) criteria is the gold standard for mRCC risk stratification. We created a risk scoring system for mRCC pts treated with C. Methods: We performed a retrospective review of 87 mRCC pts treated with C at Winship Cancer Institute from 2015-19. Overall survival (OS) and progression free survival (PFS) were defined as months from C initiation. The baseline characteristics and inflammation biomarkers included were monocyte, neutrophil, and platelet-to-lymphocyte ratios (MLR, NLR, and PLR respectively), RCC histology, body mass index (BMI), metastatic sites (mets), and Eastern Cooperative Oncology Group performance status (ECOG PS). Upon variable selection in multivariable analysis (MVA), elevated baseline MLR (≥0.71), presence of sarcomatoid histology, ECOG PS > 1, and absence of bone metastases were assigned 1 point. A three-level risk scoring system was created: low (score = 0-1), intermediate (score = 2), and high risk (score = 3-4). The Kaplan-Meier method, Cox proportional hazard model, and Uno’s C-statistics were used to examine performance. Results: The majority of pts were males (71%) with clear-cell RCC (75%). Most pts (67%) received 1+ prior line of therapy. High and intermediate risk pts had significantly shorter OS and PFS compared to low risk pts (Table). The C-statistics for our risk scoring system were higher than IMDC in predicting OS (0.7 vs. 0.62) and PFS (0.65 vs 0.57). Conclusions: Pts treated with C may benefit from risk scoring using RCC histology, ECOG PS, mets, and MLR. These results are hypothesis-generating and should be validated in a larger study.[Table: see text]