Real-world evaluation of atezolizumab and etoposide-carboplatin as a first-line treatment for extensive-stage small cell lung cancer

Background/Aims: Despite the obvious benefits of adding immune checkpoint inhibitors to platinum-etoposide chemotherapy in patients with extensive-stage small- cell lung cancer (ES-SCLC), real-world data remain scarce. Methods: This retrospective study included 89 patients with ES-SCLC treated with platinum-etoposide chemotherapy alone (chemo- only group; n = 48) or in combination with atezolizumab (atezolizumab group; n = 41) and compared the survival outcomes between these two groups. Results: Overall survival (OS) was significantly longer in the atezolizumab group than in the chemo- only group (15.2 months vs. 8.5 months; p = 0.047), whereas the median progression-free survival was almost the same (5.1 months vs. 5.0 months) in both groups (p = 0.754). Subsequent multivariate analysis revealed that thoracic radiation ( hazard ratio [HR], 0.223; 95% confidence interval [CI], 0.092- 0.537; p = 0.001) and atezolizumab administration (HR, 0.350; 95% CI, 0.184-0.668; p = 0.001) were favorable prognostic factors for OS. In the thoracic radiation subgroup, patients who received atezolizumab demonstrated favorable survival outcomes and no grade 3-4 adverse events (AEs). Conclusions: The addition of atezolizumab to platinum-etoposide resulted in favorable outcomes in this real-world study. Thoracic radiation was associated with improved OS and acceptable AE risk in combination with immunotherapy in patients with ES-SCLC.