Background: The treatment landscape is changing for patients (pts) with extensive stage small cell lung cancer (eSCLC). There’s limited data on the outcomes of treatment with current standard of care in eSCLC. We assessed the treatment outcomes including progression-free survival (PFS), overall survival (OS), and tumor response (TR) for eSCLC pts who received the 1st line (1L) treatment in community oncology settings in the United States (US). Methods: Retrospective medical records data from adults diagnosed with eSCLC between 1/1/2008 and 12/31/2017 were collected from US oncology practices. Descriptive analysis was performed on best overall TR. PFS, OS, and duration of response (DOR) were assessed using Kaplan-Meier analysis and Cox regression. Age, sex, race, stage at initial diagnosis, performance status, and comorbidity are the main variables in the Cox models. Results: Among 406 pts with eSCLC, 196 (48.3%) were male, 313 (77.1%) white, and median age was 65.1 years (range 38.5-86.0 years). Among the 346 pts who received systemic therapy, 43 (12.4%) of the pts had impaired performance (non-impaired: 303, 87.6%). Median PFS was 4.5 (impaired) and 5.3 (non-impaired) months from start of 1L treatment. Median OS was 7.2 (impaired) and 8.4 (non-impaired) months from start of 1L treatment. Cox models did not show significant difference in the risk of progression or death between impaired and non-impaired pts. However, male gender and higher comorbidity index score were both associated with significantly higher risk for progression or death (for PFS and OS analysis) at 1L. 68.7% of non-impaired pts had a TR (complete or partial response) compared to 61.4% of impaired pts within 1L of therapy. Overall median DOR was 4.4 months from the earliest occurring positive TR within the 1L of therapy to the earlier of disease progression or death. Conclusions: The study suggests that pts with eSCLC experience rapidly progressive disease as evidenced by the short PFS and DOR. The data highlight the limitations of the current standard of care with respect to high unmet need and limited survival benefit. In addition, these data provide a benchmark/historical perspective for future research focusing on the real-world effectiveness outcomes of the anticipated new immunotherapies for the treatment of 1L eSCLC.