Real-World Survival Over 25 Years in Extensive-Stage Small-Cell Lung Cancer: The Impact of Immune Checkpoint...

Therapeutic progress for extensive-stage small-cell lung cancer (ES-SCLC) has been limited. Although immune checkpoint inhibitors (ICIs) have been introduced, their real-world impact on survival remains uncertain. We evaluated 25-year survival trends and the association between ICI exposure and overall survival (OS).

Consecutive ES-SCLC patients treated at a Japanese cancer center between April 1999 and March 2023 were retrospectively reviewed and grouped by diagnosis period: A (1999-2003), B (2004-2008), C (2009-2013), D (2014-2018), and E (2019-2023). OS from diagnosis to death was measured. Kaplan-Meier/log-rank tests and multivariable Cox models were used. Subgroup analyses included patients aged ≥ 75 years, with PS ≥ 2, and with brain metastases.

A total of 452 patients were included. Median OS in period A was 9.8 months and in periods B-E, it was 12.5, 13.4, 11.8, and 13.6 months; 2-year OS rates were 6.2%, 18.2%, 18.6%, 17.3%, and 28.9%, respectively. In multivariable analysis, PS ≥ 2 (HR 1.51), receipt of first-line therapy (HR 0.09), and ICI exposure (HR 0.73; p = 0.013) were independently associated with OS. ICI exposure was associated with longer OS (15.2 vs. 12.3 months; 2-year OS 32.1% vs. 15.9%; p < 0.005) among systemically treated patients. In subgroup analyses, ICI-associated HRs were 0.67 in patients aged ≥ 75 years, 0.69 in PS ≥ 2, and 0.63 in brain metastases.

Real-world survival in ES-SCLC improved over 25 years. ICI exposure was independently associated with improved OS, as well as in clinically high-risk subgroups.