Outcomes of first-line anti-PD-L1 blockades combined with brain radiotherapy for extensive-stage small-cell lung cancer with brain metastasis.

Abstract

Anti-programmed cell death-ligand 1 (Anti-PD-L1) blockades have become the first-line treatment of extensive-stage small-cell lung cancer (ES-SCLC) from CASPIAN and IMpower133 trials. SCLC has a high incidence of brain metastasis (BM) and brain radiotherapy (BRT) is the main local treatment method, but there is limited data on the BRT-immunotherapy scheme. The aim of the retrospective study is to investigate the clinical efficacy and safety of the first-line anti-PD-L1 blockades combined with BRT in ES-SCLC with BM. Patients with newly diagnosed ES-SCLC with baseline BMs at Shandong Cancer Hospital and Research Institute between 2017 and 2021 were selected. Patients were divided into the anti-PD-L1+BRT group and BRT group. We also assessed the leukoencephalopathy in both groups. A total of 46 patients were selected. Fifteen were divided into anti-PD-L1+BRT group and 31 to BRT group. The median overall survival (OS) was not reached (NR) vs 15.9m (P = 0.172). Progression-free survival (PFS) was numerically prolonged with anti-PD-L1 blockades, but the significance was not reached (median: 9.4m vs 7.4m, P = 0.362). The median intracranial PFS was not improved, neither (median: 8.2m vs 8.9m, P = 0.620). Objective response rate (ORR) in the two groups was 73.33% vs 77.42% (P = 0.949) and disease control rate (DCR) was both 100%. Intracranial ORR and DCR were 53.33% vs 70.97% (P = 0.239) and 73.33% vs 80.65% (P = 0.855), respectively. There was no significant difference in leukoencephalopathy incidence between the two groups. The combination of first-line anti-PD-L1 blockades with BRT did not confer a significant survival benefit in ES-SCLC with BM, without enhancing cranial neurotoxicity.