Effect of peripheral blood lymphocyte-to-monocyte ratio on prognosis of esophageal cancer patients treated with intensity-modulated radiotherapy

Abstract

Objective To observe the variation trend of the peripheral blood lymphocyte-to-monocyte ratio (LMR) during radiotherapy in patients with esophageal cancer and analyze the relationship between LMR and the radiation-induced injury, aiming to provide parameters for accurate evaluation of radiotherapy responses and clinical efficacy. Methods Clinical data of 248 eligible patients undergoing definitive radiotherapy in our department from January 2013 to December 2015, 248 were retrospectively analyzed. The routine peripheral blood examination was performed weekly before, during and at the end of radiotherapy. The absolute number of lymphocyte and monocyte was recorded to calculate the LMR. The standard classification of LMR value was conducted based on the median value of each parameter. All data including the lesion length, lesion location, clinical stage and LMR were analyzed using the Kaplan-Meier, cox and logistic regression methods, respectively. Results LMR displayed an exponential decline during radiotherapy. Univariate analysis showed that the average LMR value was the influential factor of overall survival (P=0.011) and progression-free survival (P=0.017). The mean LMR value almost exerted significant effect upon local control rate (P=0.053). No significant correlation was observed between the mean LMR value and radioactive esophagitis and pneumonitis. Stratified analysis based on the results of multivariate analysis demonstrated that patients with higher average LMR value still had longer survival. Logistic regression model revealed that the length of esophageal lesion and irradiation pattern were the influential factors of the mean LMR value. Conclusions LMR value displays an exponential decline during radiotherapy. The greater amplitude prompts the worse prognosis. The wider the irradiation field and the greater decrease in LMR exert more obvious impact on the prognosis. Key words: Lymphocyte-to-monocyte ratio; Esophageal neoplasm/intensity-modulated radiotherapy; Prognosis