Pretreatment 'prognostic nutritional index' as an indicator of outcome in lung cancer patients receiving ICI-based treatment: Systematic review and meta-analysis

The pretreatment prognostic nutritional index (PNI) is an indicator of nutritional and immune status, and has potential use as a predictor of survival in cancer patients. Several retrospective studies have used the PNI to predict the outcome of lung cancer patients receiving different immune checkpoint inhibitors (ICIs), but the results have been inconsistent. The objective of our study is to assess the relationship of pretreatment PNI with survival outcomes in lung cancer patients who received ICI-based treatments by meta-analysis.We searched the EMBASE, PubMed, Cochrane Library, American Society of Clinical Oncology, and European Society of Medical Oncology databases to identify studies that reported overall survival (OS) or progression-free survival (PFS) in eligible patients. Eight studies were eligible based on predefined inclusion and exclusion criteria. Data and pooled indicators were extracted from these studies. Meta-analysis was used to analyze hazard ratios (HRs) and 95% confidence intervals (CIs) for OS and/or PFS and the prognostic value of pretreatment PNI. We completed the registration of the research protocol (Registration number: INPLASY202240087, DOI number: 10.37766/inplasy2022.4.0087).We analyzed data from 8 eligible studies (831 patients). Meta-analysis showed that relative to patients with low pretreatment PNI, those with a high pretreatment PNI had better OS (HR = 2.50, 95% CI = 1.44-4.33, P = .001) and better PFS (HR = 1.94, 95% CI = 1.56-2.42, P.001). Sensitivity analysis indicated these results were robust. There was also no evidence of publication bias.Lung cancer patients receiving ICI-based treatments who had higher pretreatment PNI had better OS and PFS.