Baseline and early changes in the neutrophil–lymphocyte ratio (NLR) predict survival outcomes in advanced colorectal cancer patients treated with immunotherapy

Systemic inflammation plays a role in carcinogenesis and is related to overall survival in patients with different cancer types, including those treated with immune checkpoint blockade (ICB). The neutrophil-lymphocyte ratio (NLR) is calculated by circulating neutrophil to lymphocyte counts, which represents an indicator of the balance between the deleterious roles of neutrophilia and the beneficial roles of lymphocyte-mediated immunity. We hypothesized that the NLR may predict outcomes in metastatic colorectal cancer (mCRC) patients treated with immunotherapy.This retrospective study included 110 mCRC patients who were treated with immunotherapy at Sun Yat-sen University Cancer Center. Several inflammatory biomarkers were measured at baseline and after two cycles of treatment. The X-tile program was used to obtain the cutoff values. We examined the impact of both baseline and posttreatment inflammatory index levels on overall survival (OS).In univariate analysis, both a low baseline NLR (P = 0.014) and a decreased NLR after 2 cycles of immunotherapy (P < 0.001) were considerably correlated with better OS. In multivariate analysis, age, liver metastasis, baseline lymphocyte-monocyte ratio (LMR), baseline NLR and early changes in NLR independently predicted OS. Patients with both a low baseline NLR and an early NLR reduction had the longest OS (median, 29.63 months). The best outcomes were remarkably observed in patients who had both an early NLR reduction and a high tumor mutational burden (TMB) (≥10 mut/Mb) (P < 0.0001).Both a low baseline NLR and an early NLR reduction are significantly associated with a better prognosis in mCRC patients treated with immunotherapy. Further analysis indicated that the combination of NLR and TMB could obtain additional predictive power.