Prognostic Significance of Peri-Treatment Inflammatory Burden Index in Patients with Rectal Cancer Undergoing...

Background/Objectives: Systemic inflammatory responses influence treatment response and oncological outcomes in patients with cancer. Growing evidence indicates that the inflammatory burden index (IBI) serves as a reliable prognostic indicator across various malignancies. However, the clinical significance of the peri-treatment inflammatory status in patients with rectal cancer (RC) undergoing preoperative chemoradiotherapy (CRT) remains unclear. Methods: We assessed the pre- and post-treatment IBI in 97 patients with RC who received preoperative CRT followed by total mesorectal excision at our institution. Results: Although no significant changes were observed in the pre- or post-CRT IBI and no associations were found with most clinicopathological factors, survival analysis revealed that a high pre-CRT IBI was significantly associated with shorter overall survival (OS) and disease-free survival (DFS). Multivariable analysis revealed that a high pre-CRT IBI and pathological lymph node metastasis remained independent prognostic factors for both outcomes. Subgroup analysis demonstrated that the prognostic value of the peri-treatment IBI differed according to the ypN status, with the pre-CRT IBI showing particularly strong prognostic performance in patients without pathological lymph node metastasis (ypN-). Conclusions: Pre-treatment assessment of the IBI may improve risk stratification in patients with RC undergoing preoperative CRT followed by curative resection.