Treatment patterns and outcomes of immunotherapy in extensive-stage small-cell lung cancer based on real-world practice.

Background: The application of immune checkpoint inhibitors (ICIs) represents a breakthrough in the current landscape for the treatment of extensive-stage small-cell lung cancer (ES-SCLC), but the real-world outcome is limited. This study aimed to investigate the treatment options and efficacy evaluation of first-line, second-line, and subsequent-line immunotherapy in routine practice.

Methods: A retrospective analysis of ES-SCLC patients treated with ICIs was conducted between May 2016 and September 2021. Objective response rate, disease control rate, progression-free survival (PFS) and overall survival were assessed between groups to explore the value of ICIs at different treatment time periods. PFS1 and PFS2 were defined as the duration from initial therapy to disease progression or death in first-line or second-line treatment.

Results: Ninety-six patients with ES-SCLC were included. PFS1 was prolonged in patients treated with first-line ICIs-combined therapy (median PFS1 7.20 months vs. 5.30 months, hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.36-087, p = 0.0085). For patients who progressed after first-line ICIs treatment (N = 22), PFS1 + PFS2 was longer in the second-line ICIs continuation group with no significant difference (median PFS1 + PFS2 11.27 months vs. 7.20 months, HR 0.45, 95% CI 0.14-1.51, p = 0.19). For patients who experienced a progression event after first-line chemotherapy (N = 50), PFS2 and PFS1 + PFS2 were prolonged in patients who accepted second-line ICIs-combined therapy without significant difference (median PFS2 4.00 months vs. 2.43 months, HR 0.59, 95% CI 0.33-1.05, p = 0.070; median PFS1 + PFS2 11.30 months vs. 8.70 months, HR 0.53, 95% CI 0.29-0.98, p = 0.056).

Conclusion: First-line ICIs plus chemotherapy should be applied in the clinical practice of ES-SCLC. If patients did not receive ICIs plus chemotherapy in first-line treatment, therapies that include ICIs in second-line treatment should be considered.