Inflammation-tumor burden interaction score stratifies survival after irinotecan-eluting bead chemoembolization for colorectal liver metastases

Background Transarterial chemoembolization with irinotecan-loaded drug-eluting beads is an established locoregional option for selected patients with colorectal liver metastases who are not candidates for resection or ablation, but survival outcomes remain heterogeneous and simple prognostic tools are lacking. Methods In this retrospective single-center study, we analyzed 70 patients treated between 2015 and 2024 to investigate whether the interaction between systemic inflammation and liver tumor burden can stratify survival after this procedure. Dynamic inflammatory change was quantified using the difference in the C-reactive protein-to-albumin ratio (ΔCAR) between baseline and early post-treatment assessments, and liver tumor burden was categorized by the number of metastases (< 5 vs. ≥ 5). These components were integrated into a composite chemoembolization–tumor burden–inflammation balance score (CT-IBS), and its association with early radiologic response, progression-free survival, and overall survival was evaluated using Kaplan–Meier analysis, receiver operating characteristic curves, and multivariable Cox regression. Results At a median follow-up of 20.3 months, median progression-free and overall survival were 9.1 and 18.9 months, respectively, and early radiologic response (complete or partial) was observed in 75.7% of patients. Higher ΔCAR and a greater number of liver metastases were independently associated with inferior overall survival. The CT-IBS stratified patients into three distinct prognostic groups (median overall survival 27.3 vs. 17.8 vs. 8.6 months; p < 0.001; area under the curve 0.703). Conclusion Integrating dynamic inflammatory changes with liver tumor burden yields a simple, reproducible classification that may support risk stratification, patient selection, and post-treatment surveillance after irinotecan-eluting bead chemoembolization for colorectal liver metastases.