Lymphocytes and Neutrophil-to-Lymphocyte Ratio Variations After Selective Internal Radiation Treatment for HCC: A Retrospective Cohort Study

Abstract

Purpose Selective internal radiation therapy (SIRT) has been proposed for combination with immunotherapy to treat hepatocellular carcinoma (HCC). However, the toxicity of radiation toward lymphocytes is understudied after SIRT. The aim of this study was to describe variations of lymphocytes following SIRT and their potential prognostic impact. Materials and Methods This is a retrospective cohort study of 164 patients treated with SIRT for HCC. Lymphocyte count and neutrophil-to-lymphocyte (NLR) ratio were evaluated at baseline and at 3 months. Primary endpoint was overall survival (OS). Results Median baseline lymphocyte count was 1.32 Giga/Liter (G/L) (standard deviation (SD) 0.64) at baseline versus 0.68 G/L (SD 0.41) at 3 months. The mean decrease of lymphocyte count was − 44% (standard deviation 0.24). At 3 months, only 21% of patients had normal (1 G/L or more) lymphocyte count, and 23% had lymphocyte count < 0.5 G/L. NLR at 3 months was significantly and independently associated with OS in multivariate Cox model. Median OS was 9.9 months (95% confidence interval (CI) 6.2–13.5) for patients with NLR at 3 months higher than 7.2 compared to 19.9 months in patients with an NLR lower that the 7.2 threshold (95% CI 16.3–23.3) (p = 0.003). Conclusions The decrease in lymphocytes was frequent and deep after SIRT for HCC. NLR increase at 3 months was associated with poor survival.