Assessing the Relationship Between Liver Metastases and the Survival of Patients With Non-Small Cell Lung Cancer After Immune Checkpoint Inhibitors Treatment: A Systematic Review and Meta-Analysis

OBJECTIVE: It is not well determined whether liver metastasis is a prognostic factor for survival of metastatic non-small cell lung cancer (NSCLC) patients who received immune checkpoint inhibitors (ICIs). We compared the efficacy of ICIs in patients with NSCLC with or without liver metastases, aiming to evaluate the impact of liver metastasis on survival of NSCLC. METHODS: We systematically searched Pubmed, Embase, and the Cochrane library databases for randomized controlled trials (RCTs) on the efficacy of ICIs in the treatment of NSCLC patients with or without liver metastases. The duration of this search was from January 1, 2000 to June 1, 2022. The reviewers screened the literature, extracted data and conducted quality assessment, and used RevMan 5.4 software and Stata 14 to perform analyses. RESULTS: A total of 17 RCTs were included, published from 2019 to 2022. For NSCLC patients with liver metastases, the risk of disease progression decreased by 36% (HR = 0.64; 95% CI: 0.55-0.75; P < .01) when treated with ICIs, and the death risk (HR = 0.82; 95% CI: 0.72-0.94; P < .01) was also reduced after ICIs treatment. For those without liver metastases, they had significantly improved PFS (HR = 0.56; 95% CI: 0.52-0.60; P < .01) and OS (HR = 0.73; 95% CI: 0.67-0.80; P < .01), compared to those of the control group. Subgroup analysis of OS in liver metastases patients suggested that OS benefit was associated with treatment strategy (for anti-PD-L1 plus chemotherapy versus chemotherapy, HR=1.04; 95% CI: 0.81-1.34; P =.75). CONCLUSION: For NSCLC patients with or without liver metastases, ICIs administration could improve both PFS and OS, especially for those without liver metastases. More RCTs are essential to verify these findings.