Adoptive immunotherapy with interleukin-2 & induced killer cells in non-small cell lung cancer: A systematic review & meta-analysis

BACKGROUND & OBJECTIVES The effectiveness of interleukin-2 (IL-2) and induced killer cells for non-small cell lung cancer (NSCLC) is controversial. This study evaluates the efficacy and safety of interleukin-2 and induced killer cells on NSCLC, so as to provide references for further clinical practice and research. METHODS Relevant randomized controlled trials (RCTs) were searched in Cochrane library (Issue 2, 2013), Web of Science (1980-March 2013), PubMed (1966-March 2013), China Knowledge Resource Integrated database (CNKI) (1994-March 2013), China Biology Medicine database (CBM) (1978-March 2013), VIP (1989-March 2013), and Wan Fang databases (1997-March 2013). There were no language restrictions. After independent quality assessment and data extraction by two authors, meta-analysis was conducted by RevMan 5.1 software. RESULTS Ten RCTs were included. Odds ratio (OR), 95% confidence intervals (CI), P value expressed as test group (interleukin-2 or induced killer cells combined chemotherapy) versus control group (chemotherapy alone), was 2.02 (1.24, 3.29; P=0.004) for disease control rate. Hazard ratios (HR) (95% CI; P value), expressed as test group (interleukin-2 or induced killer cells) versus control group, were 0.60 (0.46, 0.79; P=0.0003) for overall survival of postoperative treatment, and 0.77 (0.60, 0.99; P =0.04) for overall survival of combination with chemotherapy. Mean differences (MD) (95% CI; P value), expressed as test group (interleukin-2 or induced killer cells) versus control group (after treatment), were 11.32 (6.32, 16.33; P=0.00001) for NK cells, 11.79 (2.71, 20.86; P=0.01) for CD3+ cells, 14.63 (2.62, 26.64; P=0.02) for CD4+ cells, and -4.49 (-7.80, 1.18; P=0.008) for CD8+ cells. INTERPRETATION & CONCLUSIONS The meta-analysis showed that IL-2 or induced killer cells combination therapy was efficacious in treating NSCLC and improved overall survival. Further analysis of trials having adequate information and data need to be done to confirm these findings.