Clinical Feasibility of Six Inflammatory Markers for Predicting the Mortality of Patients With Cancer: Longitudinal Study

Abstract Background Emerging evidence indicates that inflammation plays a crucial role in cancer prognosis. Inflammatory response biomarkers are recognized as promising prognostic factors for mortality in patients with cancer. Objective This study aims to evaluate the prognostic significance of the systemic inflammatory response index (SIRI), systemic immune-inflammation index (SII), platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), inflammatory prognostic index (IPI), and C-reactive protein-albumin-lymphocyte (CALLY) index. Methods Weighted Cox regression analyses, restricted cubic spline models, Kaplan-Meier survival curves, and receiver operating characteristic analyses were performed to assess the predictive value of the 6 inflammatory markers for mortality. Subgroup analyses and sensitivity analyses were conducted to examine associations within specific subpopulations. Results Cox regression models demonstrated that SIRI, NLR, IPI, and CALLY were significant predictors of all-cause mortality (tertile 3 vs tertile 1; hazard ratio [HR]: SIRI: 1.72, 95% CI 1.29‐2.27; NLR: 1.33, 95% CI 1.02‐1.74; IPI: 1.48, 95% CI 1.14‐1.92; CALLY: 0.66, 95% CI 0.51‐0.85). IPI (HR 1.91, 95% CI 1.11‐3.27) and CALLY (HR 0.53, 95% CI 0.31‐0.90) were significantly associated with cancer-specific mortality, whereas only SIRI was able to predict cardiovascular mortality ( P value for trend=.04). Dose-response relationships were observed between the 6 inflammatory markers and mortality outcomes. Kaplan-Meier survival curves further illustrated significant differences between tertile groups (log-rank test, P <.001). The 6 inflammatory indices exhibited moderate predictive ability for all-cause mortality. IPI yielded the highest area under the curve (AUC) for cancer-specific mortality (AUC=0.6338), and SIRI was the most efficient predictor of cardiovascular mortality (AUC=0.687). No significant interactions were observed between the 6 inflammatory markers and most subgroup variables. Conclusions SIRI, NLR, IPI, and CALLY represent convenient and cost-effective prognostic tools for predicting mortality in patients with cancer. In contrast, SII and PLR may not be reliable prognostic biomarkers.