Organ-specific efficacy in advanced non-small cell lung cancer patients treated with first-line single-agent immune checkpoint inhibitors

BACKGROUND: Response to immune checkpoint inhibitors (ICIs) is affected by multiple factors. This study aimed to explore whether sites of metastasis are associated with clinical outcomes of ICIs in advanced non-small-cell lung cancer (NSCLC) patients. METHODS: The data of NSCLC patients with high programmed death-ligand 1 expression and good performance status receiving first-line ICIs monotherapy from Guangdong Provincial People's Hospital between May 2019 and July 2020 were retrospectively analyzed. Metastatic sites included liver, bone, brain, adrenal gland, pleura, and contralateral lung. Progression-free survival (PFS) and overall survival (OS) were compared between different metastatic sites and metastatic burden by the Kaplan-Meier method. Organ-specific disease control rate (OSDCR) of different individual metastatic sites was evaluated. RESULTS: Forty NSCLC patients meeting the criteria were identified. The presence of liver metastasis was significantly associated with shorter PFS (3.1 vs. 15.5 months, P = 0.0005) and OS (11.1 months vs. not reached, P = 0.0016). Besides, patients with bone metastasis tend to get shorter PFS (4.2 vs. 15.5 months, P = 0.0532) rather than OS (P = 0.6086). Moreover, the application of local treatment could numerically prolong PFS in patients with brain metastasis (15.5 vs. 4.3 months, P = 0.1894). More metastatic organs involved were associated with inferior PFS (P = 0.0052) but not OS (P = 0.0791). The presence of liver metastasis or bone metastasis was associated with more metastatic organs (Phi[ϕ]: 0.516, P = 0.001). The highest OSDCR was observed in lung (15/17), and the lowest in the liver (1/4). CONCLUSIONS: Metastases in different anatomical locations may be associated with different clinical outcomes and local tumor response to ICIs in NSCLC. ICIs monotherapy shows limited efficacy in patients with liver and bone metastasis, thus patients with this type of metastasis might require more aggressive combination strategies.