Objective To compare the short-term efficacy of pulsed low-dose-rate radiotherapy (PLDR) and three-dimensional conformal intensity-modulated radiotherapy (IMRT) in the treatment of recurrent esophageal carcinoma, and to assess their effects on peripheral blood T-lymphocyte subsets.Methods A total of 98 patients with recurrent esophageal cancer admitted to Heping Hospital Affiliated to Changzhi Medical College between January 2022 and January 2025 were selected and randomized using a random number table into an observation group (PLDR) and a control group (IMRT), each comprising 49 patients. The efficacy, post-treatment serum carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC), vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9), peripheral blood CD3⁺, CD4⁺, and CD4⁺/CD8⁺, and adverse reactions were compared between the two groups.Results The overall response rate in the observation group was higher than that in the control group (P < 0.05). Following treatment, levels of CA19-9, CEA, SCC, VEGF and MMP-9 in the observation group were all lower than those in the control group (P < 0.05). In both groups, levels of CA19-9, CEA, SCC, VEGF and MMP-9 were lower after treatment than before treatment (P < 0.05). In the observation group, levels of CD3⁺, CD4⁺, and CD4⁺/CD8⁺ were all higher than in the control group after treatment (P < 0.05). In both groups, levels of CD3⁺, CD4⁺, and CD4⁺/CD8⁺ were all higher after treatment than before treatment (P < 0.05). The SSA score in the observation group after treatment was lower than that in the control group (P < 0.05). The SSA scores in both groups after treatment were lower than those before treatment (P < 0.05). The incidence of acute radiation esophagitis, acute radiation pneumonitis and the overall incidence of adverse reactions were all lower in the observation group than in the control group (P < 0.05).Conclusion PLDR can enhance the efficacy of treatment for recurrent esophageal cancer, improve patients' swallowing function, downregulate tumor microenvironment factors such as CA19-9, CEA and SCC, protect T-lymphocyte immune function, and reduce the incidence of severe radiation damage.