Developing and validating a Modified Cachexia Index to predict the outcomes for colorectal cancer after radical surgery.

Background: It was reported that the cachexia index (CXI: $\frac{\mathrm{ALB}*\mathrm{SMI}}{\mathrm{NLR}}$ ) was an essential index for predicting the prognosis of tumor patients. However, since for SMI needs to be measured by CT imaging methods and its calculation was inconvenient. Thus, we developed a modified cachexia index (mCXI: $\frac{\mathrm{ALB}}{\mathrm{NLR}*\mathrm{UCR}}$ ). The purpose of this study was to evaluate the association between mCXI and prognosis in patients with colorectal cancer.

Methods: An analysis of 215 patients with newly diagnosed colorectal cancer was carried out retrospectively. An optimal cut-off value of mCXI was established by the receiver operating characteristic (ROC) curves for predicting prognosis. Prognostic implications of mCXI were investigated using Kaplan-Meier curves and Cox regression analysis. A comparative assessment of the predictive capacity between mCXI and the CXI was performed using time-dependent receiver operating characteristic analysis.

Results: Patients were classified into two groups based on the cut-off value of mCXI: the LOW mCXI group (n = 60) and the HIGH mCXI group (n = 155). The 3-year Overall survival (OS) (76.6% vs 96.7%, p < 0.01) and 3-year Recurrence-free survival (RFS) (68.3% vs 94.1%, p < 0.01) were significantly worse in the LOW mCXI group in contrast to that in the HIGH mCXI group. In Cox multivariate regression analysis, mCXI was an independent prognostic factor for OS (HR = 8.951, 95%CI: 3.105-25.807, <0.01). Moreover, compared with CXI (AUC = 0.723), mCXI (AUC = 0.801) has better predictive efficacy, indicating that mCXI is more suitable for prognostic assessment.

Conclusions: The mCXI significantly correlated with survival outcomes for colorectal cancer patients after radical surgery.