Comparison between immunotherapy efficacy in early non-small cell lung cancer and advanced non-small cell lung cancer: a systematic review

Abstract Background Currently, immunotherapy is widely used in the treatment of various stages of non-small cell lung cancer. According to clinical experience and results of previous studies, immunotherapy as neoadjuvant therapy seems to exhibit better efficacy against early resectable non-small cell lung cancer as compared to advanced lung cancer, which is often defined as unresectable non-small cell lung cancer. However, this observation has not been established in clinical studies. This systematic review aimed to evaluate the efficacy of immunotherapy in early and late lung cancer, wherein objective response rate (ORR) and disease control rate (DCR) were used as evaluation indexes. The present study also evaluated the safety of immunotherapy in early and late lung cancer, wherein the rate of treatment-related adverse reactions (TRAEs) was used as an indicator. Methods Electronica databases, including PubMed, Cochrane Library, Embase, and other databases, were searched to identify relevant studies. Besides this, all the available reviews, abstracts, and meeting reports from the main international lung cancer meetings were searched manually. ORR, DCR, and TRAEs were extracted as the primary outcomes. Results A total of 52 randomized controlled trials involving 13,660 patients were shortlisted. It was observed that immunotherapy alone significantly improved DCR in early lung cancer in comparison to advanced lung cancer. Importantly, the improvement in ORR was not to the same extent as reported in the case of advanced lung cancer. The combination of immunotherapy with other therapies, especially immunochemotherapy, significantly improved ORR and DCR in early lung cancer. In terms of safety, immunotherapy either alone or in combination with other therapies exhibited a better safety profile in early lung cancer than in advanced lung cancer. Conclusions Altogether, the benefits of immunotherapy in early lung cancer appeared to be better than those observed in advanced lung cancer, especially with the regard to the regimen of immunotherapy in combination with chemotherapy. In terms of safety, both immunotherapy alone and its combination with chemotherapy were found to be safer in early lung cancer as compared to advanced lung cancer.