Novel risk scoring system for metastatic renal cell carcinoma patients treated with cabozantinib

Cabozantinib is an effective treatment for metastatic renal cell carcinoma (mRCC). The international mRCC database consortium (IMDC) criteria is the gold standard for risk stratification in mRCC. We created a risk scoring system specific for mRCC patients treated with cabozantinib.

We conducted a retrospective review of 87 patients with mRCC treated with cabozantinib at Winship Cancer Institute from 2015 to 2019. Overall survival (OS) and progression free survival (PFS) were used to measure clinical outcomes. Upon variable selection in multivariable analysis (MVA), elevated baseline monocyte-to-lymphocyte ratio (MLR), sarcomatoid histologic component, ECOG PS > 1, and absence of bone metastases were each assigned 1 point. A three-group risk scoring system was then created: low (score=0-1), intermediate (score=2), and high risk (score=3-4). The Cox proportional hazard model and Kaplan-Meier method were used for survival analyses.

The median age was 62 years-old and the majority were males (71%) with clear-cell RCC (75%). Most (67%) received at least 1 prior line of systemic therapy. High risk and intermediate risk pts had significantly shorter OS (high risk HR: 13.84, p<0.001; intermediate risk HR: 3.50, p = 0.004) and PFS (high risk HR: 7.31, p<0.001; intermediate risk HR: 1.87, p = 0.053) compared to low risk patients in MVA.

RCC patients treated with cabozantinib may benefit from specific risk stratification criteria using RCC histology, ECOG PS, sites of metastatic disease, and MLR. These variables are easily accessible in the clinical setting and may be helpful to determine which mRCC patients may benefit from treatment with cabozantinib.