Long-term outcomes in extensive disease small cell lung cancer patients treated without immune checkpoint inhibitors

Immune 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.

We 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.

A 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.

We 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.