Experience and safety of chemotherapy and immunotherapy in patients with small cell lung cancer.

e20132 Background: The majority of patients (Pts) diagnosed with small cell lung cancer (SCLC) present with advanced-stage disease at diagnosis, therefore being associated with a poor prognosis. Chemotherapy (CT) associated with immunotherapy (IO) has revolutionized the treatment of SCLC. The objective of our study is to evaluate the efficacy and safety in Pts with SCLC treated with CT and IO in the first-line treatment in the Huelva area. Methods: This is a descriptive and observational study in Pts with SCLC who received first-line treatment with carboplatin, etoposic and atezolizumab from 2021 to 2025 in the Huelva area (Spain). SPSS Statistics 22 was used for data analysis. Results: 11 Pts were treated, median age 61 years and 72% men. ECOG PS 0-1 in all Pts. 100% were in stage IV at diagnosis and none of them had brain metastases. 54.5% of Pts achieved partial disease response, while 45.5% presented disease progression. 45% of Pts currently maintain treatment, with the median number of months alive being 9 months. Median progression-free survival (PFS) was 4 months (95% CI: 2.8 – 5.2) and the median overall survival (OS) was 3 months (95% CI: 0 – 7). The results in the first case were statistically significant, but not in the second. 45.5% of patients presented toxicity of any grade (G), 50% G1-2 and 50% G3-4. The most frequent adverse event was anemia (37%, 27% G1 and 10% G3), followed by 18% G3 neutropenia. One case of grade 3 neurotoxicity secondary to treatment was also observed. No immune-mediated effects were recorded. Conclusions: Based on our results regarding the IMPOWER 133 study, we consider that CT associated with IO as a first-line treatment for SCLC has an acceptable safety profile, with less frequent side effects. PFS and OS were lower in our study because most patients are still alive, which is a limitation of our study along with the small sample size. Despite this, we conclude that CT associated with IO is an effective therapy that changes the treatment paradigm in SCLC.