Abstract: Objective To investigate the clinical value of the inflammatory burden index (IBI) in the diagnosis and prognosis of colorectal cancer. Methods A total of 350 patients with colorectal cancer diagnosed pathologically in the First Affiliated Hospital of Xi'an Medical University from January 2017 to January 2022 were selected as the study subjects, and 350 healthy individuals who underwent physical examinations during the same period were selected as the control group. The receiver operating characteristic(ROC) was used to analyze the value of IBI in the diagnosis and prognosis prediction of colorectal cancer. Univariable and multivariable Cox regression models were used to analyze the associations of IBI and clinical indicators with prognosis of colorectal cancer. A nomogram was established to predict the survival rate. Results The ROC curve analysis showed that IBI was statistically significant in the diagnosis of colorectal cancer (Z=12.382, P<0.001). The area under the curve (AUC) was 0.813 (95%CI: 0.774-0.848), and the best cut⁃off point was 25.52. IBI was also statistically significant in predicting the prognosis of colorectal cancer (Z=9.473, P<0.001). The AUC was 0.824 (95%CI: 0.771-0.869), and the best cut⁃off point was 33.68. Univariable Cox regression analysis showed that higher IBI was correlated with higher preoperative CEA and worse T and N staging (P<0.05). Multivariable Cox regression analysis showed that IBI>33.68 was an independent risk factor affecting the prognosis of colorectal cancer patients(HR=3.576, 95%CI: 3.114-4.138). The overall C⁃index of the nomogram model was 0.849 (95%CI: 0.829-0.868, P<0.001). The calibration curve showed good consistency between the predicted survival rate and the actual survival rate. Conclusions IBI >33.68 is an independent prognostic risk factor for colorectal cancer. IBI has good diagnostic and prognostic value and may be a new biomarker for colorectal cancer.

Key words: Colorectal cancer, Inflammatory burden index, Diagnosis, Prognosis