Aim: We conducted a systematic review and network meta-analysis to evaluate the efficacy of immunotherapy versus chemotherapy to treat extensive-stage small-cell lung cancer. Methods: We analyzed several eligible clinical trials using fixed or random-effects models to evaluate relative treatment effects depending on heterogeneity. Results: In the experimental group, immunotherapy showed significant improvement in overall survival (hazard ratio [HR]: 0.82; 95% CI: 0.74-0.89; I2 = 31.4%; p < 0.001) and progression-free survival (HR: 0.77; 95% CI: 0.80-0.83; I2 = 22.7%; p < 0.001). Conclusion: Immunotherapy is likely to significantly improve extensive-stage small-cell lung cancer patients' overall survival and progression-free survival compared with standard chemotherapy. Anti-PD L1 exhibited superior overall survival compared with anti-PD 1 and anti-CTLA4.
Keywords: chemotherapy; cytotoxic T-lymphocyte antigen-4; extensive-stag small-cell lung cancer; immune checkpoint inhibitor; programmed death 1; programmed death 1 ligand 1.
Lay abstract In the past decades, therapy of small-cell lung cancer (SCLC) has maintained the status quo in that etoposide, in combination with platinum-based chemotherapy, is still the first-line treatment for SCLC. Despite cancer cells being very sensitive to standard chemotherapy, relapse rates and prognosis are poor, especially in extensive-stage small-cell lung carcinoma (ES-SCLC). It is meaningful that immune checkpoint inhibitors have led to a promising transformation of treatment models for ES-SCLC. We searched the related literature systematically and performed a meta-analysis of several clinical trials to compare chemotherapy's therapeutic efficacy with immunotherapy. We found that immune checkpoint inhibitors achieve great improvement in survival indexes of ES-SCLC patients compared with standard chemotherapy.