Antiprogrammed death ligand 1 therapy failed to reduce the risk of developing brain metastases in patients with extensive-stage small cell lung cancer: A retrospective analysis

Abstract

Background: Immunotherapy (IO) has demonstrated promising results in treating extensive-stage small cell lung cancer (ES-SCLC), and the management of ES-SCLC brain metastases (BMs) is now receiving significant clinical attention. The objective of this study was to evaluate the role of IO in the clinical management of BMs.

Methods: Between January 2020 and December 2021, the study included the records of 250 patients who were diagnosed with ES-SCLC. Overall survival (OS), progression-free survival, intracranial progression-free survival, and the cumulative incidence of BMs were calculated using the Kaplan-Meier method and were compared using the log-rank test. In addition, the Cox regression model was used to analyze prognostic factors.

Results: In the entire group, 85 patients had baseline BMs (IO plus chemotherapy [IO + ChT], n = 38; ChT alone, n = 47), and 165 patients (IO + ChT, n = 86; ChT alone, n = 79) did not have BMs at the time of initial diagnosis. The median follow-up was 22.4 months. The OS benefit with first-line antiprogrammed death ligand 1 therapy was maintained regardless of whether patients had BMs (with BMs, 17.97 vs. 13.14 months [p = .03]; without BMs, 18.46 vs. 15.05 months [p = .047]). However, in patients without BMs, IO did not delay the median time to developing brain progression (10.84 vs. 10.74 months; p = .84), and it did not significantly reduce the risk of developing intracranial metastases (the 2-year actuarial risk of developing BMs was 57.0% vs. 50.6%, respectively).

Conclusions: Antiprogrammed death ligand 1 therapy improved OS regardless of the presence of BMs. However, IO did not delay the median time to brain progression or reduce the risk of intracranial metastasis in patients without baseline BMs. The findings of this study have important clinical implications for the future management of BMs from ES-SCLC.

Keywords: brain metastases (BMs); chemotherapy (ChT); disease progression pattern; extensive-stage small cell lung cancer (ES-SCLC); immunotherapy (IO); programmed death ligand 1 (PD-L1) checkpoint inhibitors.