Clinical efficacy and safety of CIK plus radiotherapy for lung cancer: A meta-analysis of 16 randomized controlled trials

Objective Cytokine-induced killer cells (CIK) therapy is the most commonly used cellular immunotherapy. The CIK plus radiotherapy was clinically used in a wide range of treatment, but the efficacy of their combination against lung cancer is not clear yet. Therefore, we systematically evaluated all the related studies to reveal the combination's clinical efficacy and safety in lung cancer. Materials and methods We collected all the studies about CIK plus radiotherapy for lung cancer in Medline, Embase, Web of Science (ISI), China National Knowledge Infrastructure Database (CNKI), Chinese Scientific Journals Full-Text Database (VIP), Wanfang Database, China Biological Medicine Database (CBM) and Cochrane Central Register of Controlled Trials (CENTRAL), Chinese clinical trial registry (Chi-CTR), WHO International Clinical Trials Registry Platform (WHO-ICTRP) and US-clinical trials (March 2017). We evaluated their bias risk according to the Cochrane evaluation handbook of randomized controlled trials (RCTs), extracted all the data, and synthesized the data using meta analysis. Results We included 16 RCTs involving 1197 patients with lung cancer, and most trials had unclear risk of bias. Meta-analysis showed that CIK therapy could increase the objective response rate (ORR) (1.32, 1.21 to 1.44), the disease control rate (DCR) (1.13, 1.04 to 1.23), the 1-year overall survival (OS) rate (1.38, 1.16 to 1.63) and the 2-year OS rate (1.23, 1.11 to 1.35). DCs-CIK cells increased the 3-year OS rate (1.66, 1.20 to 2.29). DCs-CIK therapy could increase the CD3+T cells (2.27, 1.47 to 3.06), CD4+T cells (1.28, 0.74 to 1.81), NK cells (2.04, 0.74 to 3.33) and CD4+/CD8+ T cells ratio (1.20, 0.64 to 1.76) and decrease the CD8+T cells (−0.84, −1.60 to −0.08). CIK plus radiotherapy had lower risk of leukopenia (0.85, 0.76 to 0.95) and higher risk of fever (5.50, 2.71 to 11.17) than that of radiotherapy alone. Subgroup analysis showed that CIK plus radiotherapy, mainly three dimensional conformal radiotherapy (3D-CRT) could increase the ORR, DCR, 1- and 2- year OS rate in non-small cell lung cancer (NSCLC), and only DCR in small cell lung cancer (SCLC). Compared with CIK plus pure radiotherapy, except for the ORR, DCR, 1-year OS rate, CIK plus chemoradiotherapy could still increase the 2-year OS rate. DCs-CIK could increase the ORR, DCR, 1- and 2-year OS rate, CIK cells could only increase the ORR and the 1-year OS rate. Conclusions CIK plus radiotherapy can improve the clinical response, OS and PFS in lung cancer. It may have low risk of leukopenia and high risk of fever. CIK plus chemoradiotherapy, mainly 3D-CRT can improve the clinical response, OS and PFS in NSCLC. DCs-CIK cells can improve the 1-, 2- and 3-year OS rate, and the 1- and 2-year PFS rate, and CIK cells only improve the 1-year OS rate. DCs-CIK cells can repair the antitumor immunity.