A nomogram combining NLR, PLR and SII to predict progression-free survival of cetuximab-based first-line therapy in patients with metastatic colorectal cancer

Abstract Objective: To establish an effective prognostic nomogram combining neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII) to predict progression-free survival (PFS) of metastatic colorectal cancer (mCRC) patientstreated with cetuximab-based first-line therapy. Materials and methods: 143 patients with mCRC were admitted to our hospital and received cetuximab-based first-line therapy. The patients were separated into training and validation cohorts. Patients' baseline blood parameters and clinical characteristics were collected. In the training cohort, Kaplan-Meier analysis, univariate analysis, and multivariate analysis were used to identify factors associated with PFS and to screen for independent predictors. A prognostic nomogram was constructed, and the model's predictive efficacy, stability and net benefit were evaluated. Validation was performed in the validation cohort. Results: Kaplan-Meier analysis showed that patients in the NLR≥3.9 group, PLR≥152.2 group and SII≥464.3 group had worse PFS than those in the NLR<3.9 group, PLR<152.2 group and SII<464.3 group, respectively ( P <0.001). Univariate analysis revealed that the resected primary tumor, liver metastases, NLR, PLR and SII were significantly correlated with PFS. Multivariate analysis revealed that the resected primary tumor (HR: 0.551, 95%CI: 0.329-0.924, P =0.024), liver metastases (HR: 2.033, 95%CI: 1.212-3.407, P =0.007), NLR (HR: 2.596, 95%CI: 1.378-4.888, P =0.003), PLR (HR: 2.002, 95%CI: 1.235-3.246, P =0.005) and SII (HR: 2.202, 95%CI: 1.292-3.751, P =0.004) were independent prognostic factors affecting PFS. A prognostic nomogram model was developed and revealed the greatest predictive efficacy (AUC=0.870). The nomogram revealed excellent stability and predictive value in both training (C-index=0.827) and validation cohort (C-index=0.870). Decision curve analysis (DCA) proved that the prognostic nomogram could be clinically valuable. Conclusions: The nomogram combining the resected primary tumor, liver metastases, NLR, PLR, and SII can be used to predict the PFS of mCRC patients treated with cetuximab-based first-line therapy.