Prognostic Value of Perineural Invasion in Esophageal and Esophagogastric Junction Carcinoma: A Meta-Analysis

Objective. Here we aimed to clarify the prognostic significance of perineural invasion (PNI) in esophageal and esophagogastric junction (EGJ) carcinoma. Methods. A comprehensive literature search for relevant reports published up to July 2015 was performed using Pubmed and Embase databases. The pooled HR and 95% CI for overall survival (OS) and disease-free survival (DFS) were used to assess the prognostic value. The association of PNI with pathological characteristics was evaluated by OR and 95% CI. Results. A total of 13 cohorts were retrieved, covering 2770 patients treated by surgery. The cumulative analysis revealed a statistical correlation between PNI and poor OS (HR = 1.76, 95% CI: 1.54–2.20, and P < 0.00001), as well as poor DFS (HR = 1.96, 95% CI: 1.42–2.71, and P < 0.001). Moreover, analysis of 1475 patients showed improved PNI in T3 + T4 (OR = 0.39, 95% CI: 0.21–0.70, and P = 0.002), N+ (OR = 0.52, 95% CI: 0.40–0.69, and P < 0.00001), and G3 + G4 (OR = 0.66, 95% CI: 0.48–0.90, and P = 0.008) patients compared with T1 + T2, N−, and G1 + G2 ones, respectively. No significant heterogeneity was found between the studies. Conclusions. PNI is an adverse prognostic biomarker in esophageal and EGJ carcinoma. Moreover, PNI implies advanced T, N stage and poor cell differentiation.