Background: Myelosuppression is common in patients with extensive-stage small-cell lung cancer (ES-SCLC) receiving chemotherapy and poses a high burden for patients and oncology practices. This study described burden of myelosuppression among patients with ES-SCLC treated with chemotherapy using data from Tennessee Oncology, one of the largest community-based cancer care specialists in US, providing cancer care at over thirty locations. Methods: Data from Dec 2019 to Feb 2023 were collected from structured electronic medical records supplemented by chart review. Adult patients with ES-SCLC initiating chemotherapy (with or without immunotherapy) during Jan 2020 to Jun 2022 were identified. The baseline period was 30 days before index (chemotherapy initiation date) and the follow-up period was from index date through end of data availability or date of death, whichever was the earliest. Outcomes included prevalence of grade ≥3 myelosuppression, cytopenia-related healthcare utilization, and all-cause healthcare resource utilization (HRU). This analysis focused on patients without use of multilineage myeloprotection therapy. Results: The analysis included152 patients. Mean ± standard deviation (SD) age at index was 66.7 ± 9.5 years and 50% were male. Most patients were white (89.5%), with 0 or 1 Eastern Cooperative Oncology Group score (73.7%) and had a first-line ES-SCLC treatment of carboplatin, etoposide, and atezolizumab (85.5%). Grade ≥3 myelosuppression during baseline was minimal (<1%). Patients were followed for an average of 10.2 ± 7.0 months. Grade ≥3 myelosuppression was common during follow-up (≥1 lineage: 63.8%; ≥2 lineages: 32.2%; 3 lineages: 10.5%) (Table). Cytopenia-related healthcare utilization included granulocyte colony-stimulating factor use (76.3%), intravenous hydration (61.8%), red blood cell transfusion (30.3%), and erythropoiesis-stimulating agents (18.4%), iron infusion (8.6%), and platelet transfusions (7.2%). All-cause HRU included 57.9% with ≥1 inpatient admission (length of stay: 8.4 ± 7.3 days; per patient 0.8 ± 0.9 admissions) and 67.8% with ≥1 emergency room visit (per patient 1.1 ± 1.2 visits). Conclusions: There is high patient burden associated with traditional management of myelosuppression in patients with ES-SCLC in a community oncology practice, indicating an unmet need in this population.