Abstract
Lung cancer is the most commonly diagnosed cancer among men and it is the third ranked in women. There are two major types of lung cancer, namely, small cell lung cancer (SCLC), which accounts for ~20% of the cases, and non-small cell lung cancer (NSCLC), which is the most common. Chemotherapy and chemoradiotherapy have been used as the first-line therapies but suffer from lack of efficacy and also of several toxic adverse effects. Immunotherapeutic approaches including tumor antigen vaccination, monoclonal antibodies targeting checkpoint pathways and also activated immune cells are being developed and have been shown to be effective in treating NSCLC. Despite their promise, efficacy of several immunotherapies has not been consistent. We undertook this meta-analysis study to analyze results from clinical trials that compared efficacy and safety of immunotherapies with placebo or chemotherapy/radiotherapy in improving overall survival (OS) and progression-free survival (PFS) of NSCLC patients. Various databases were searched to identify randomized clinical studies examining the efficacy and safety of antibody- and vaccine-based immunotherapies in NSCLC patients in comparison to chemotherapy or chemoradiotherapy or placebo. Effects on OS and PFS and also adverse events have been compared. In accordance with the selection criteria, a total of 13 studies with 3,513 patients in immunotherapy and 3,072 patients in chemotherapy/placebo, were selected. PFS (odds ratio 1.81, 95% CI 1.36, 2.42; P<0.0001) and OS (P<0.0001) are found to be greatly improved by immunotherapies. Immunotherapy of NSCLC patients was also found to prevent several adverse effects and to improve daily living ability of the patients. The present meta-analysis strongly suggests that immunotherapy improves OS and PFS of patients with NSCLC.