Analysis of first-line combination of carboplatin and etoposide plus atezolizumab in the treatment of extensive stage small cell lung cancer: A retrospective study

Background and Aim: Recently, clinical studies have revealed that combination of chemotherapy with immune checkpoint inhibitors provide significant survival benefit in extensive-stage small cell lung cancer (ES-SCLC). Real life data showed that effectiveness and safety of this approach differ from those in clinical studies due to the heterogeneity of patients in real-life scenarios. Our study aims to assess the effectiveness and toxicity profile of atezolizumab with carboplatin-etoposide chemotherapy in the first-line treatment of ES-SCLC by considering the demographic and clinical characteristics of patients in our community. Method: This is a multicenter and retrospective study. 46 patients with ES SCLC who received first-line carboplatin, etoposide, and atezolizumab. between March 2019 and June 2023. Statistically, Cox regression and Kaplan-Meier methods were used to evaluate survival parameters. Results: Based on statistical analyses, the median progression-free survival (PFS) was determined to be 7.6 months (95% CI 5.8-9.4), and the median overall survival (OS) was found to be 12.8 months (95% CI 8.0-17.7). It was observed that consolidative thoracic radiotherapy (cTRT) is associated with better PFS. Additionally, female gender and low LDH levels were correlated with better OS. Conclusion: Our study demonstrates the effectiveness and safety of the combination of carboplatin, etoposide, and atezolizumab in the first-line treatment of ES-SCLC. However, extensive and prospective studies with longer follow-up periods are needed to identify markers predicting immunotherapy response in ES-SCLC and to demonstrate the long-term effects of chemoimmunotherapy on survival. Keywords: Atezolizumab, Consolidative Thoracic Radiotherapy, Small Cell Lung Cancer, Survival