SYSTEMIC INFLAMMATION RESPONSE INDEX AS A PREDICTOR OF DISTANT METASTASIS IN BREAST CANCER PATIENTS

Abstract

Introduction: Systemic Inflammation Response Index (SIRI) reflects systemic inflammation and immune response. Elevated SIRI has been linked to poor cancer outcomes by promoting tumor progression and metastasis. This study evaluates the relationship between pre-treatment SIRI and distant metastasis in breast cancer patients.

Methods: This retrospective cross-sectional study analyzed medical records of breast cancer patients at Margono Soekarjo County Hospital between 2022 and 2024, with 869 patients included for analysis. Pre-treatment SIRI was calculated from complete blood count parameters. Metastatic status was confirmed by imaging and/or histopathology. SIRI was defined as neutrophils and monocytes divided by lymphocytes. Statistical analyses included comparison of SIRI between metastatic and non-metastatic groups, ROC analysis, and multivariable logistic regression to evaluate the discriminative ability and independent association of SIRI with distant metastasis, adjusting for age, histopathological type, and molecular subtype.

Results: Pre-treatment SIRI was significantly higher in the metastatic group than in the non-metastatic group (mean ± SD: 2.49 ± 2.68 vs. 0.41 ± 0.49; p < 0.001). ROC analysis identified an optimal SIRI cut-off of >0.60, yielding 86% sensitivity, 85% specificity, and an AUC of 0.90, indicating excellent discriminatory performance. In multivariable logistic regression, higher SIRI independently predicted distant metastasis after adjustment of the confounding factors, with each one-unit increase associated with substantially increased odds (adjusted OR = 12.28; 95% CI: 8.22–18.33; p < 0.001.

Conclusion: Pre-treatment SIRI showed an association with distant metastasis in breast cancer, indicating its potential as low-cost and non-invasive prognostic biomarker.