Efficacy of cytokine-induced killer cell infusion as an adjuvant immunotherapy for hepatocellular carcinoma: a systematic review and meta-analysis

This study was designed to evaluate the efficacy and safety of cytokine-induced killer (CIK) cell-based immunotherapy as an adjuvant therapy for hepatocellular carcinoma (HCC). Published studies were identified by searching Medline, Cochrane, EMBASE, and Google Scholar databases with the keywords: cytokine-induced killer cell, hepatocellular carcinoma, and immunotherapy. The outcomes of interest were overall survival, progression-free survival, and disease-free survival. Eight randomized controlled trials (RCTs), six prospective studies, and three retrospective studies were included. The overall analysis revealed that patients in the CIK cell-treatment group had a higher survival rate (pooled hazard ratio (HR) =0.594, 95% confidence interval [CI] =0.501–0.703, P<0.001). Patients treated with CIK cells in non-RCTs had a higher progression-free survival rate (pooled HR =0.613, 95% CI =0.510–0.738, P<0.001). However, CIK cell-treated patients in RCTs had progression-free survival rates similar to those of the control group (pooled HR =0.700, 95% CI =0.452–1.084, P=0.110). The comparison between pooled results of RCTs and non-RCTs regarding the progression-free survival rate did not reach statistical significance. Patients in the CIK cell-treatment group had lower rates of relapse in RCTs (pooled HR =0.635, 95% CI =0.514–0.784, P<0.001). Similar results were found when non-RCT and RCTs were pooled (pooled HR =0.623, 95% CI =0.516–0.752, P<0.001). Adjuvant CIK cell-based immunotherapy is a promising therapeutic approach that can improve overall survival and reduce recurrence in patients with HCC.