Adjuvant cytokine-induced killer cell immunotherapy for hepatocellular carcinoma: a propensity score-matched analysis of real-world data

Background: Several randomized controlled trials have shown that adjuvant immunotherapy with autologous cytokine-induced killer (CIK) cells prolongs recurrence-free survival (RFS) after curative treatment for hepatocellular carcinoma (HCC). We investigated the efficacy of adjuvant immunotherapy with activated CIK cells in real-world clinical practice. Methods: A total of 59 patients who had undergone curative surgical resection or radiofrequency ablation for stage I or II HCC, and subsequently received adjuvant CIK cell immunotherapy at two large-volume centers in Korea were retrospectively included. Propensity score matching with a 1:1 ratio was conducted to avoid possible bias, and 59 pairs of matched control subjects were also generated. The primary endpoint was RFS and the secondary endpoints were overall survival and safety. Results: The median follow-up duration was 28.0 months (interquartile range, 22.9-42.3 months). In a univariable analysis, the immunotherapy group showed significantly longer RFS than the control group (hazard ratio [HR], 0.42; 95% CI, 0.22-0.80; log-rank P = 0.006). The median RFS in the control group was 29.8months, and the immunotherapy group did not reach a median RFS. A multivariable Cox proportional hazard analysis showed that immunotherapy was an independent predictor for HCC recurrence (adjusted HR, 0.38; 95% CI, 0.20-0.73; P = 0.004). The overall incidence of adverse events in the immunotherapy group was 16/59 (27.1%) and no patient experienced a grade 3 or 4 adverse event. Conclusions: The adjuvant immunotherapy with autologous CIK cells after curative treatment safely prolonged the RFS of HCC patients in a real-world setting.