Objective: This meta-analysis was designed to explore the association between the systemic immune-inflammation index (SII) and the therapeutic effect of immune checkpoint inhibitors. Materials & methods: The authors retrieved relevant studies published before May 25, 2022. Hazard ratio (HR) with 95% CI was used to evaluate the relationship between SII and overall survival (OS) and progression-free survival (PFS). Results: 14 articles comprising 2721 patients were included in this study. The pooled results proved that high SII levels were closely related to poor prognosis in cancer patients receiving immune checkpoint inhibitors (OS HR = 2.40; 95% CI: 2.04-2.82; PFS HR = 1.57; 95% CI: 1.33-1.86) and that an SII value of 750 was appropriate as a cut-off value (OS HR = 2.20; 95% CI: 1.83-2.63; PFS HR = 1.54; 95% CI: 1.33-1.80). Conclusion: High SII levels (>750) may be an indicator of worse OS and PFS in cancer patients treated with immune checkpoint inhibitors.
Keywords: cancer; immune checkpoint inhibitor; meta-analysis; prognosis; systemic immune–inflammation index.
Immune checkpoint inhibitors (ICIs) have substantially improved the prognosis of many patients with advanced cancer. However, some patients still do not benefit from ICIs. Therefore, determining indicators that can identify patients who may benefit from ICIs is essential. As a noninvasive, convenient and inexpensive clinical indicator, the systemic immune–inflammation index is expected to solve the aforementioned issue. Through this meta-analysis, the authors demonstrated that patients with cancers with high systemic immune–inflammation index levels had shorter survival and a smaller degree of clinical benefit after ICI treatment. Moreover, a systemic immune–inflammation index value of 750 is recommended to be the cut-off value for stratifying patients.