AbstractObjectiveImmune checkpoint inhibitors (ICIs) combined with chemotherapy have been approved as first-line treatment for patients with untreated extensive disease-small cell lung cancer (ED-SCLC). However, there are few reports about the long-term outcomes in patients with ED-SCLC treated without ICIs. Thus, we analyzed the long-term outcomes in patients with ED-SCLC.MethodsWe retrospectively examined the medical records of patients with SCLC who were treated at our hospital between September 2002 and September 2019. The main inclusion criteria were as follows: (i) histological or cytological confirmation of SCLC, (ii) diagnosed with ED-SCLC and (iii) received chemotherapy, not including ICIs, as the first-line treatment. To assess the trends of treatment outcomes, we compared the survival outcomes between 2002–2010 (early) and 2011–2019 (late) groups.ResultsA total of 314 patients were included in this study. Patient characteristics at the time of first-line treatment were as follows: median age was 69 years; 82% of the patients were male and 70% had a performance status of 0 or 1. The median follow-up time of overall survival (OS) was 7.4 years, and 89% of the patients died. The median progression-free survival and survival time were 4.9 and 12.1 months, respectively. Five-year survival rate was 2%. There was no significant difference in survival between the early and late groups.ConclusionsWe found that the long-term outcomes in ED-SCLC patients treated without ICIs were poor. Prior to the approval of ICI treatment for ED-SCLC, there was no improvement in the OS for ~20 years.