Real-World Analysis of Clinical Characteristics and Survival Outcomes in Patients With Extensive-Stage SCLC Treated With First-Line Chemoimmunotherapy

Introduction: There are no clinically validated prognostic biomarkers in the management of extensive-stage SCLC (ES-SCLC). We explored the association between clinical characteristics and survival outcomes in patients with ES-SCLC treated with chemoimmunotherapy. Methods: In this retrospective cohort study, patients with ES-SCLC treated with first-line platinum-etoposide chemotherapy and atezolizumab were identified from medical records. Pretreatment clinical characteristics, biochemical parameters, and tumor and treatment characteristics were collected. Univariate and multivariate Cox regression were used to evaluate treatment effect on progression-free survival (PFS) and overall survival (OS). Results: We evaluated 75 patients in total. The median PFS and OS were 6.1 months and 9.2 months, respectively. Statistically significant associations were found with lower lactate dehydrogenase and improved OS (hazard ratio [HR] = 1.0, 95% confidence interval [CI]: 1.0–1.01, p = 0.006), whereas higher age (HR = 0.94, 95% CI: 0.90–0.98, p = 0.006) and lower neutrophil-to-lymphocyte ratio (HR = 1.08, 95% CI: 1.02–1.14, p = 0.005) were associated with improved PFS. The number of chemotherapy cycles received were associated with both an improved PFS (HR = 0.57, 95% CI: 0.37–0.89, p = 0.011) and OS (HR = 0.5, 95% CI: 0.30–0.84, p = 0.008). Conclusions: This study highlights the important effect of chemotherapy on survival. Furthermore, the association between lactate dehydrogenase and neutrophil-to-lymphocyte ratio on survival further suggests that baseline tumor burden and optimizing sarcopenia are important factors for clinicians to consider as we seek to develop personalized treatment for this disease.