Outcomes of immunotherapy (ICI) alone vs tyrosine kinase inhibitors (TKI) alone versus ICI and TKI combined in renal cell carcinoma brain metastasis.

Abstract

2030 Background: Renal cancer is the fourth most common cause of metastatic tumors to the brain. Tyrosine kinase inhibitors (TKIs) targeting VEGFR and other receptors, such as sunitinib, pazopanib, etc., have been used as first line for renal cell carcinoma brain metastasis (RCCBM). Immune Checkpoint Inhibitors (ICIs) targeting PD-L1 and CTLA-4 interactions, such as nivolumab and ipilimumab respectively, have also been used as first line treatment for RCCBM. However, the efficacy of TKIs alone, ICIs alone, or TKIs and ICIs combined as first line treatment has emerged as a topic of interest. Methods: Patients with RCCBM treated with either TKIs, ICIs, or both at our tertiary care center from 2010-2019 were evaluated. Overall Survival (OS) was measured from initiation of either TKI or ICI therapy to date of death or last follow up. The Cox proportional hazard model was used to determine differences in OS. Results: 218 patients with RCCBM were included. Of these, 32 were treated with ICIs alone, 112 were treated with TKIs alone, and 76 were treated with a combination of ICIs and TKIs. For ICI treatment alone the median age at diagnosis was 61 years (Interquartile range (IQR) 38-82), 72% of the patients were male, and 97% were white. For TKI treatment alone the median age at diagnosis was 58 years (IQR 37-82), 70% of the patients were male, and 92% were white. For the combination cohort the median age at diagnosis was 63 years (IQR 45-79), 69% of the patients were male, and 97% were white. OS for patients receiving ICI, TKI, and combination treatment had a median of 69.1, 42.7, and 126.0 months and a 2-year rate of 77%, 69%, and 93%, respectively. With ICI treatment as a reference, TKI treated patients had an OS hazard ratio of 1.32 (95% CI = 0.78 - 2.21, p = 0.30) and ICI/TKI combination had an OS hazard ratio of 0.52 (95% CI = 0.30 - 0.92, p = 0.024). Conclusions: A combination treatment of ICIs and TKIs was associated with an increase in OS when compared to treatment with either TKIs or ICIs alone in patients with RCCBM. These results should be interpreted cautiously due to treatment selection bias. Further studies need to be done to control for other patient variables such as performance status, number of intracranial lesions, and extra-cranial metastasis.[Table: see text]