Background: Small cell lung cancer (SCLC) is highly invasive and fatal, sensitive to chemotherapy and radiotherapy but prone to relapse, with a poor overall survival rate. It is particularly urgent for SCLC patients to receive effective follow-up treatment. In the past 20 years, there has been no breakthrough in clinical treatment of SCLC. Currently, clinical studies on immunotherapy for SCLC with extensive stage disease (ED) have achieved good efficacy, bringing new hope for the treatment of small-cell lung cancer. PD-1 inhibitors used to treat small cell lung cancer include Pembrolizumab and Nivolumab. PD-L1 inhibitors mainly include Atezolizumab and Durvalumab. Other PD-1/PD-L1 inhibitors, such as Avelumab, are currently being tried for SCLC and the results have not yet been published. This study is to evaluate the efficacy and safety of immunotherapy in patients with ED SCLC.
Methods: A literature search of the PubMed, Embase, and Cochrane Library databases were performed. Two reviewers independently screened the literature, extracted the data, and evaluated the risk of bias of the included studies. RevMan 5.3 software was used for meta-analysis.
Results: Four studies involving 1,981 patients with ED SCLC were included. Both overall survival (OS) [hazard ratio (HR) =0.80, 95% confidence interval (CI) (0.68, 0.95), P=0.009] and progression-free survival (PFS) [HR =0.82, 95% CI (0.75, 0.90), P<0.00001] were longer in the immunotherapy group than in the chemotherapy group. The incidence of total treatment-related adverse events in the immunotherapy group were lower than those in the chemotherapy group [relative risk (RR) =1.050, 95% CI (1.010, 1.080), P=0.007], and the differences were statistically significant.
Conclusions: Immunotherapy has better efficacy and safety than chemotherapy for the treatment of ED SCLC.
Keywords: Immunotherapy; chemotherapy; small cell lung cancer.