Background: The systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) are commonly used prognostic indicators for a variety of cancers. However, their utility in oral cancers is unknown. We systematically examined evidence on the ability of SII and SIRI to predict overall survival (OS) and disease-free survival (DFS) after oral cancers.
Material and methods: Embase, PubMed, Web of Science, and Scopus were searched for oral cancer studies reporting OS or DFS based on SII or SIRI. Articles published up to 25th May 2024 were included.
Results: 17 studies were eligible (14 on SII and 3 on SIRI). Pretreatment high SII scores were found to be significantly linked with poor OS (HR: 1.62 95% 1.26, 2.08 I2=88%) and DFS (HR: 1.62 95% 1.25, 2.27 I2=86%) after oral cancer. Similarly, high SIRI was associated with worse OS in oral cancer patients (HR: 1.60 95% 1.31, 1.94 I2=0%). All results were unchanged on sensitivity analysis. Subgroup analysis based on location, cancer type, sample size, treatment, cut-off, methods of determining cut-off, analysis method, and study quality showed mixed results.
Conclusions: Acknowledging the limitations of current evidence, it seems that both SII and SIRI can predict the prognosis of oral cancers. High SII and SIRI are both associated with worse OS while high SII also predicts worse DFS.