Predictive role of the monocyte-to-lymphocyte ratio in advanced hepatocellular carcinoma patients receiving anti-PD-1 therapy

Background: The immune checkpoint inhibitor (ICIs) therapy has been proven effective in a range of solid tumors including hepatocellular carcinoma (HCC), non-small cell lung carcinoma and metastatic melanoma. However, only a subset of approximately 20% of patients shows an objective response to anti-PD-1 therapy in HCC. Furthermore, the response to anti-PD-1 therapy is not correlated with programmed cell death 1 ligand expression in tumor tissue. Therefore, it is urgent to identify a biomarker to predict the response of anti-PD-1 therapy. Methods: This retrospective study was conducted at the Fudan University Shanghai Cancer Center from December 2019 to June 2021. The monocyte-to-lymphocyte ratio (MLR) was analyzed using a receiver operating characteristic (ROC) curve. A Cox regression model and the log-rank test were used to analyze the relationship between the MLR value and the time to progression (TTP). Results: A total of 34 advanced HCC patients were enrolled in this study. The cut-off point for the MLR at baseline was 0.35. Univariate and multivariate Cox regression models showed that the MLR at baseline was significantly correlated with the TTP (P<0.05). Consistent results were found for disease progression. The log-rank test showed that patients in the low MLR group had a longer TTP (P=0.0027). At the time of disease progression, the median TTP in the low and high MLR groups were 33 and 18 weeks, respectively (P=0.0047). Conclusions: The MLR can predict the response to anti-PD-1 therapy, and a high MLR is correlated with a short TTP in anti-PD-1-treated HCC patients.