The prognostic value of pre-treatment prognostic nutritional index in esophageal squamous cell carcinoma

Abstract Background: Prognostic nutritional index (PNI) is an easily obtained index inflecting both one's nutritional and inflammatory status. Its clinical role in esophageal squamous cell carcinoma (ESCC) remains still in debate. The aim of this meta-analysis was to assess the prognostic value and the clinical-pathological features of pre-treatment PNI in ESCC patients. Methods: A comprehensive search of online databases (PubMed, Embase, Web of Science) was performed. Studies explored the relationship between pre-treatment PNI and long-term survival of ESCC patients were regarded eligible for this meta-analysis. Outcomes were extracted and synthesized. Hazard ratio (HR) and relative ratio (RR) with 95% confidence interval (CI) were used to evaluate the prognostic value of PNI on long-term survival and association with clinical-pathological features, respectively. The heterogeneity levels and publication bias between studies were also estimated. Results: Nine observational studies involving 2276 patients were considered eligible for this meta-analysis. The pooled results showed that low PNI score was significantly correlated with poorer overall survival (OS) of esophageal cancer (pooled HR = 1.418 95%CI: 1.200–1.676, P = .000), poorer recurrence free survival (HR = 1.880 95%CI: 1.207–2.929, P = .005) but not cancer specific survival (CSS) (HR = 1.948 95%CI: 0.544–6.977, P = .306). The PNI value was not related with patient age, sex, depth of tumor invasion, nodular metastasis, and differential grade but the TNM stage (III/IV vs 0/I/II, RR = 1.276, 95% CI 1.146–1.420). Conclusions: Low pre-treatment PNI was significantly related with OS and recurrence free survival but not CSS for ESCC. PNI was a reliable prognostic factor of ESCC, and higher stage ESCC have higher incidence of low PNI.