Combined Assessment of CEA and Systemic Immune-Inflammation Index in Metastatic Colorectal Cancer: A Single-Center Retrospective Study
Nadide Demirel Aydın11Department of Medical Oncology, Zonguldak Atatürk State Hospital, Zonguldak, Türkiye
Objectives: To evaluate the prognostic significance of CEA and SII and their combined assessment in metastatic colorectal cancer (mCRC). Methods: This retrospective single-center study included 80 patients with mCRC treated at our institution between January 2021 and December 2025. CEA and hematological parameters for SII were obtained from medical records. Cutoff values were determined by receiver operating characteristic analysis. Patients were classified into low- and highlevel groups, and a three-tier classification was established according to combined CEA-SII status. OS and PFS were analyzed using Kaplan-Meier and Cox regression analyses. Results: Cutoff values for OS were 4.65 ng/mL for CEA and 826.1 for SII. Elevated CEA was associated with shorter OS and PFS. In multivariate analysis, elevated CEA independently predicted poor OS (HR, 3.676; 95% CI, 1.435-9.418; p=0.007). SII alone was not independently prognostic. However, the combined CEA-SII group independently predicted OS, with each increase in risk category associated with a 77.5% higher risk of death (HR, 1.775; 95% CI, 1.171-2.689; p=0.007). The combined group was associated with PFS in univariate but not multivariate analysis. Conclusion: Elevated CEA independently predicts OS in mCRC, whereas SII alone does not. CEA-SII assessment provides additional prognostic information for OS and may facilitate risk stratification. Keywords: Biomarker, carcinoembryonic antigen, metastatic colorectal cancer, overall survival, prognosis, systemic immune-inflammation index
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Demirel Aydın N. Combined Assessment of CEA and Systemic Immune-Inflammation Index in Metastatic Colorectal Cancer: A Single-Center Retrospective Study. EJMI. 2026; 10(4): 618-627
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