Systemic immune-inflammation index predicts the clinical outcome in patients with metastatic renal cell cancer treated with sunitinib

Background: In this retrospective analysis, we explored the prognostic and predictive value of the systemic immune-inflammation index (SII), based on lymphocyte, neutrophil, and platelet counts, at baseline and changes at week 6 during first-line sunitinib in patients with metastatic renal cell cancer (RCC). Results: Patients were stratified into high SII (≥ 730) and low SII (< 730) groups. SII was associated with objective response, p < 0.0001. The median PFS was 6.3 months (95% CI 5.5-8.9) in patients with SII = 730 and 18.7 months (95% CI 14.7-22.8) in those with SII < 730, p < 0.0001. The median OS was 43.6 months (95% CI 35.3-52.1) in patients with SII < 730, and 13.5 months (95% CI 9.8-18.5) in those with SII ≥ 730, p < 0.0001. In multivariate analysis, performance status, IMDC score and SII were able to predict OS (HR = 3.29, HR = 1.71 and HR = 1.79, respectively). Materials and Methods: We included 335 consecutive RCC patients treated with first-line sunitinib. The X-tile 3.6.1 software (Yale University, New Haven, CT) was used for bioinformatic analysis of the data to determine the cutoffvalue of SII. Progression-free survival (PFS), overall survival (OS) and their 95% confidence interval (95% CI) were estimated by Kaplan-Meier method and compared with logrank test. The impact of SII conversion at week 6 of treatment on PFS and OS was evaluated by Cox regression analyses. Conclusions: The SII and its changes during treatment represent a powerful prognostic indicator of clinical outcome in patients with metastatic RCC.