203P Treatment patterns and real-world outcomes of extensive-stage small cell lung cancer: A retrospective, multicenter study

Randomized phase III clinical trials showed improved survival outcomes for the combination of first-line chemotherapy and immunotherapy (CT-IO) compared to chemotherapy alone for extensive-stage small cell lung cancer (ES-SCLC). However, real-world data remain scarce. Our retrospective multicenter study aimed to evaluate the real-world impact of CT-IO in ES-SCLC patients. Data from consecutive ES-SCLC patients, from 11 Italian centers, treated with first line atezolizumab combined with chemotherapy or chemotherapy alone (platinum-etoposide) were analyzed. The co-primary outcomes were progression-free survival (PFS) and overall survival (OS). A total of 131 patients treated from October 2019 to April 2023 were included (median n. patients/centre n=13). The median age at the diagnosis was 68 years; 69% (n=90) were men and 94% (n=123) had smoking history. CT-IO was administered to 106 patients, while 25 received CT. The median number of CT and CT-IO cycles was 3 and 4, respectively, while that of maintenance IO was 4. Main reasons not to administer CT-IO were Eastern Cooperative Oncology Group performance status (PS)≥2 (28% of CT vs 7.5% of CT-IO) and advanced age (median 74 vs 68 years). A statistically significant difference was observed comparing CT-IO vs CT in terms of PFS and OS (median 7.2 vs 2.9 months, p<0.0001; 9.5 vs 3.5 months, p<0.0001, respectively). In the CT-IO cohort, brain metastases were associated with worse OS (4.6 vs 10.8 months, p=0.016). None of patients treated for ES-SCLC received a prophylactic cranial irradiation and whole brain radiotherapy was administered in 8. In the same cohort, numerically shorter OS was observed in those with liver metastases (mOS 7.1 vs 11.2 months) although the difference was not statistically significant (p=0.27). No new safety signals were observed. This study confirms the high impact of CT-IO for ES-SCLC patients in real-world. The difference in terms of PFS and OS between the two groups should be interpreted with caution considering the higher age and the worse PS for the CT group.