The Role of Pre-treatment Inflammatory Biomarkers in the Prediction of an Early Response to Panitumumab in Metastatic Colorectal Cancer

Background Systemic inflammation is a critical component of the development and progression of several types of cancer. Neutrophil-lymphocyte ratio (NLR) and lymphocyte-monocyte ratio (LMR) are simple, inexpensive, and reliable predictors of the systemic inflammatory response to the therapy in different malignant tumors, including colorectal cancer. Methods Metastatic colorectal cancer (mCRC) patients treated with panitumumab plus chemotherapy at first-line at the medical oncology unit of Fondazione Institute for Research, Hospitalization and Health Care (IRCCS) Policlinico San Matteo di Pavia between January 1st 2016 and February 1st 2021 were retrospectively analyzed. NLR and LMR were divided into two groups (high and low) based on the cut-off points, with the estimation of the prognostic accuracy of NLR for the early treatment response as the primary end-point of this study. Results The receiver operating characteristic (ROC) analysis showed a fair prognostic accuracy of NLR for early treatment response (area under the curve (AUC)=0.76, 95% CI: 0.62-0.89). A slightly lower prognostic accuracy was found for LMR (AUC=0.71, 95% CI: 0.57-0.85). In the univariable proportional hazard Cox model, no effect of NLR on PFS was found (NLR(High) vs. NLR(Low) HR=1.3; 95% CI: 0.7-2.4, p=0.414). Patients with higher levels of LMR showed a trend towards higher PFS (LMR(High) vs. LMR(Low) HR=0.4; 95% CI: 0.2-1.1, p=0.066). No association was found between NLR (or LMR) and skin toxicity. Conclusions NLR and LMR may be used as biomarkers of prognostic accuracy for the early treatment response in mCRC patients treated with panitumumab.