Pretreatment prognostic nutritional index as a prognostic factor in lung cancer: Review and meta-analysis

Background: Numerous studies have explored the association between pretreatment prognostic nutritional index (PNI) and prognosis in lung cancer (LC), but the results are still inconclusive. We systematically evaluated the prognostic value of pretreatment PNI in LC patients by conducting a meta-analysis. Methods: A comprehensive literature search was performed by retrieving PubMed, EMBASE, and Web of Science, Wan Fang and CNKI databases. We used hazard ratios (HRs) and their 95% confidence intervals (CIs) to assess the associations of PNI with overall survival (OS), disease-free survival/recurrence-free survival (DFS/RFS) and progression-free survival (PFS) in LC patients. Results: A total of 21 studies were enrolled into this meta-analysis, with 17 about no-small cell lung cancer (NSCLC) and 4 about on small-cell lung cancer (SCLC). The results indicated that NSCLC patients with low PNI had shorter OS (HR: 1.59, 95% CI: 1.28-1.96, P = 0.001), DFS/RFS (HR = 1.74, 95% CI = 1.08-2.80, P = 0.017), and PFS (HR = 1.52, 95% CI = 1.26-1.83, P = 0.002) than patients with high PNI. The robustness of these pooled results were verified by our stratified analysis and sensitivity analysis. Besides, a pooled analysis of 4 studies about SCLC suggested that low PNI was closely associated with worse OS in SCLC patients as well. Conclusion: Low PNI predicts poor survival in LC patients.