Background  Programmed death receptor-1 inhibitors have prolonged survival for esophageal cancer patients, but it remains challenging to explore mature independent predictive biomarkers for screening patients benefiting from immunotherapy.

  Objective  To evaluate the predictive value of peripheral blood lymphocyte-to-monocyte ratio (LMR), and provide practical experience for clinical screening of highly beneficial immunotherapy populations.

  Methods  Clinical data and peripheral blood test results of 202 esophageal cancer patients treated with PD-1 inhibitors from July 2016 to June 2021 in the department of oncology, the First Medical Center of Chinese PLA General Hospital were collected. Progression-free survival (PFS) and overall survival (OS) were recorded to evaluate the prognosis. ROC analysis was applied to define an optimal cut-off for peripheral blood LMR, and the patients were divided in two groups according to the cut-off value. The correlation between peripheral blood LMR and immunotherapy prognosis was analyzed.

  Results  There were 182 male patients and 20 female patients, with a median age of 61 years. In these esophageal cancer patients treated with PD-1 inhibitors, baseline LMR level was an independent risk factor for prognosis. Patients with low LMR level at baseline had poor progress-free survival (HR 95% CI: 2.383 1.355-4.191, P=0.003) and overall survival (HR 95% CI: 2.702 1.542-4.733, P<0.001) than patients with high LMR level. Conclusion For patients with esophageal cancer treated with PD-1 inhibitor, peripheral blood LMR level may be used as an independent predictor of prognosis.