The study aims to evaluate the treatment outcomes in a group of patients with extensive small cell lung cancer at Thai Nguyen Central Hospital. From June 2023 to June 2024, we conducted a descriptive cross-sectional study, both retrospective and prospective, on 31 patients with extensive  stage disease small cell lung cancer who received chemotherapy at Thai Nguyen Central Hospital from January 2014 to June 2024. The results showed that the treatment response rate was 80.7%. Patients with a performance status PS = 1 had a significantly higher complete response rate compared to those with a PS = 0 (p < 0.05). Other factors such as age, chemotherapy regimen, and dosage did not show significant differences in complete response rates. The median overall survival time was 14.0 ± 3.38 months, with survival rates of 93.5%, 54.8%, 19.1%, and 7.6% at 6, 12, 24, and 36 months, respectively. Patients aged ≥ 50 years had a higher overall survival time compared to those < 50 years (14.0 ± 2.51 months vs. 12.0 ± 4.08 months; p = 0.379). The median overall survival time for patients with a PS of 0 was 17.0 ± 3.34 months, higher than that for patients with a PS of 1 (12.0 ± 2.06 months; p = 0.163).