Long-term clinical efficacy of cytokine-induced killer cell-based immunotherapy in early-stage esophageal squamous cell carcinoma

Background aims In this retrospective clinical study, the authors investigated the impact of cytokine-induced killer (CIK) cell-based immunotherapies on the long-term survival of patients with esophageal squamous cell carcinoma (ESCC). Methods A total of 87 patients with ESCC who received comprehensive treatment were enrolled in the study. Of these patients, 43 were in the control group and 44 were in the CIK treatment group. Flow cytometry analysis was performed to detect the phenotype and anti-tumor function of CIK cells. Clinical characteristics were compared between these two groups, and the survival estimates of ESCC patients were determined using Kaplan–Meier analysis. Results CIK cells contained a high proportion of the main functional fraction (CD3+CD56+ group) and exhibited a strong killing ability for esophageal cancer cells in vitro. Importantly, overall survival (OS) and progression-free survival (PFS) were significantly higher in the CIK group than in the control group in early-stage ESCC. However, patients with advanced-stage ESCC did not benefit from CIK cell-based therapy in terms of OS and PFS compared with the control group. Conclusions These results demonstrate that CIK cells combined with conventional treatments potentially prolong long-term survival of patients and may serve as a combined therapeutic approach for the treatment of early-stage ESCC.