Effect of immune checkpoint inhibitors at different treatment time periods on prognosis of patients with extensive-stage small-cell lung cancer

Abstract

Background: The application of immune checkpoint inhibitors (ICIs) in treating patients with extensive-stage small-cell lung cancer (ES-SCLC) has brought us new hope, but the real-world outcome is relatively lacking. Our aim was to investigate the clinical use, efficacy, and survival benefit of ICIs in ES-SCLC from real-world data analysis.

Methods: A retrospective analysis of ES-SCLC patients was conducted between 2012 and 2022. Progression-free survival (PFS) and overall survival (OS) were assessed between groups to evaluate the value of ICIs at different lines of treatment. PFS1 was defined as the duration from initial therapy to disease progression or death. PFS2 was defined as the duration from the first disease progression to the second disease progression or death.

Results: One hundred and eighty patients with ES-SCLC were included. We performed landmark analysis, which showed that compared to the second-line and subsequent-lines ICIs-combined therapy group (2SL-ICIs) and non-ICIs group, the first-line ICIs-combined therapy group (1L-ICIs) prolonged OS and PFS1. There was a trend toward prolonged OS in the 2SL-ICIs group than in the non-ICIs group, but the significance threshold was not met (median OS 11.94 months vs. 11.10 months, P = 0.14). A longer PFS2 was present in the 2SL-ICIs group than in the non-ICIs group (median PFS2 4.13 months vs. 2.60 months, P < 0.001).

Conclusion: First-line ICIs plus chemotherapy should be applied in clinical practice. If patients did not use ICIs plus chemotherapy in first-line therapy, the use of ICIs in the second line or subsequent lines of treatment could prolong PFS2.

Keywords: Extensive-stage small-cell lung cancer (ES-SCLC); Immunotherapy; Lines of treatment; Prognostication.