A Low Proportion Of Regulatory T Cells Before Chemoradiotherapy Predicts Better Overall Survival In Esophageal Cancer

Background: Growing evidence indicates that survival is correlated with immune status in certain types of solid tumors. The immune system functions either to eliminate cancer cells or to keep cancer cells in check by maintaining an equilibrium; if there is a malfunction in the immune system, immune escape may happen which then allows cancer cells to grow into clinically apparent tumors. The progression of the tumor leads to a poor prognosis. Regulatory T cells (Tregs), a subset of CD4+ T cells plays a pivotal role in regulating the immune system. Tregs were identified as being CD4+ T cells expressing high levels of CD25. The purpose of this study was to investigate the influence of the proportion of pretreatment regulatory T cells (CD45+CD4+CD25(HI)CD127(LOW)) on the prognosis of patients with non-operative chemoradiotherapy for esophageal cancer (EC).Methods: A total of 297 patients with non-operative chemoradiotherapy EC treated at the Shanxi Province Cancer Hospital from January 2015 to January 2020 were included in the study. The correlation between regulatory T cell proportion and clinicopathological characteristics was analyzed by the chi-square test, while univariate survival analysis was carried out using the Kaplan-Meier method. Independent prognostic factors for overall survival (OS) were determined by univariate and multivariate Cox proportional regression models.Results: Of the clinicopathological features analyzed, tumor location and the proportion of CD4+CD8+ double-positive cells were significantly associated (P<0.05) with the proportion of pretreatment regulatory T cells. An assessment of the prognoses showed that patients with a high proportion of regulatory T cells had a significantly worse OS than patients with a low proportion of regulatory T cells. The OS of patients with a low proportion CD4+CD8+ cells was lower than that of patients with a high proportion of CD4+CD8+ cells. A high proportion of CD4+CD8+ (>3.45%) cells and a low proportion of regulatory T cells (<= 5.15%) would have better OS before chemoradiotherapy.Conclusions: Regulatory T cells play a role in predicting the prognosis of patients with EC before chemoradiotherapy.