Survival Prediction by Baseline Systemic Immune-inflammation Index (SII) and its Changes During First-line Platinum-based Treatment in a Caucasian Population of Patients With Metastatic Urothelial Carcinoma (MUC)

Background/Aim: Systemic immune-inflammation index (SII) predicts survival of patients with various malignancies. This study explored the prognostic value of SII in metastatic urothelial carcinoma (MUC) subjects. Patients and Methods: We evaluated 181 consecutive MUC patients treated with first-line platinum-based therapy. Karnofsky performance status <80% and visceral metastasis were present in 18.2% and 46.4% of patients, respectively. SII was based on platelet × neutrophil/lymphocyte counts. Study population was dichotomized by median into high and low SII groups before the initiation of chemotherapy and at week 6. Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan–Meier method and compared with the log-rank test. Results: At median follow-up of 9.6 months, 174 patients experienced disease progression and 173 died. Patients with low SII at baseline and at week 6 had significantly better PFS (HR=0.58; p=0.0002 and HR=0.55; p<0.0001) and OS (HR=0.54; p<0.0001 and HR=0.54; p<0.0001) compared to patients with high SII. Independent prognostic value of SII was confirmed in a multivariate analysis. Conclusion: High SII before chemotherapy that persists at week 6 negatively affects survival. SII at baseline can be used in the stratification of patients within clinical trials and in clinical practice.