The Relationship Between Systemic Immune Inflammation Index and Treatment Response in Renal Cell Carcinoma Patients Treated with Tyrosine Kinase Inhibitors: Results from The Turkish Oncology Group Kidney Cancer Consortium Database

Aim: To investigate the prognostic value of the systemic immune-inflammation index (SII) and its impact on survival in patients with metastatic renal cell carcinoma (mRCC).Methods: A total of 706 patients with mRCC treated with tyrosine kinase inhibitors (TKIs) (i.e., sunitinib, pazopanib) were retrospectively analyzed. All patients were classified into either a high-SII group or a low-SII group based on the cut-off value of SII at 756, which was the median SII level of our study group. Results: The median age of patients was 60 (interquartile range (IQR):53-67) years. Three out of four patients were male. The majority of patients (85.7%) had clear cell histology, and sarcomatoid differentiation was observed in 16.9% of all patients. The rates of patients in favorable, intermediate, and poor “International mRCC Database Consortium (IMDC)” risk groups were 20.1%, 57.6%, and 22.2%, respectively. There were 311 and 310 patients in the SII-low and SII-high groups, respectively. At the median of 48.6 months follow-up, the median overall survival (OS) was 34.6 months and 14.5 months in the low- and high-SII groups, respectively (p<0.001). In multivariate analysis, SII was an independent prognostic factor for OS (hazard ratio (HR):1.39, 95% confidence interval (CI):1.05-1.85, p=0.01) and PFS (HR:1.60, 95% CI:1.24-2.05, p<0.001).Conclusion: Pre-treatment level of high SII might be considered as a predictor of poor prognosis in patients with mRCC treated with TKIs.