Abstract 5970: Differences in survival outcomes based on timing and location of initial systemic therapy in patients with extensive stage small cell lung cancer

Abstract Background: Lung cancer is the leading cause of cancer deaths in the United States with small cell lung cancer comprising 20% of lung cancers and extensive stage small cell lung cancer (ES-SCLC) making up two thirds of these cases. ES-SCLC has a median progression free survival (PFS) of 5.2 months and overall survival (OS) of 13 months when treated with chemoimmunotherapy. Inpatient hospitalization for the patient’s first cycle of therapy is often utilized. We aimed to identify whether location of treatment (inpatient vs outpatient) and timing of treatment have significant survival effects. Methods: A retrospective chart review was done on ES-SCLC patients diagnosed and treated with standard of care systemic therapy between 2018-2023. Date of diagnosis, location of patient’s first cycle (inpatient vs outpatient), treatment type and dates, progression dates, death dates, and hospice enrollment dates were obtained. Survival analysis was completed using Cox-regression and log-rank test. Fischer’s exact test was used to compare differences in categorical data. Results: 48 patients were identified—40 received their first cycle outpatient and 8 inpatient. Those who received their first cycle of therapy inpatient had worse OS compared to those who received it outpatient (median 126 days vs 408 days, p=0.002). None of the patients who were initially treated inpatient received immunotherapy (IO) with their first cycle. Proportion of patients who enrolled in hospice did not differ significantly between the inpatient and outpatient groups (80% vs 65%, p=0.70). Patients treated with IO within 6 weeks of diagnosis were found to have worse PFS compared to those treated after 6 weeks (median 178 days vs 236 days, p=0.034). OS did not differ significantly. Patients enrolled in hospice were more likely to have worse OS (HR: 2.2, p=0.05). Those with PFS <6 months did not show significantly different OS if they enrolled in hospice. Amongst patients who had PFS >6 months, hospice enrollment was associated with worse OS compared to those who did not enroll in hospice, (median 465 days vs 908 days, p=.006). Conclusions: Patients who received their initial cycle of therapy inpatient had worse OS compared to those who began treatment outpatient. At our institution, IO is not administered inpatient. Further analyses show timing of IO did not significantly impact OS. However, those who received IO earlier did have worse PFS. These findings suggest that factors associated with inpatient treatment, such as more aggressive disease or significant medical comorbidities may contribute to the observed worse OS. Additionally, while hospice enrollment was associated with worse OS, the difference disappeared when analyzing patients with PFS <6 months, indicating that hospice enrollment itself may not directly impact survival in this subgroup. Citation Format: Andrea Y. Lo, Zahra Hamedi, Taharah Islam, Erin Alesi, Jonathan Berkman. Differences in survival outcomes based on timing and location of initial systemic therapy in patients with extensive stage small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5970.