Objective  To evaluate the impact of perineural invasion (PNI) on the overall survival (OS) of patients with gastric cancer.

  Methods  A total of 1, 007 patients with gastric cancer who underwent curative resection between January 2011 and December 2012 at the Cancer Institute and Hospital of Tianjin Medical University were enrolled. All the patients were categorized into the following two groups according to the status of PNI: positive group, presence of PNI; and negative group, absence of PNI. Potential prognostic factors and clinical pathological variables correlated with the presence of PNI were analyzed.

  Results  One hundred and twenty (11.9%) patients had PNI. Multivariate analysis revealed that histology, depth of invasion, and lymphovascular invasion were independently associated with the presence of PNI. Univariate survival analysis revealed that age, tumor location, Borrmann type, tumor size, curability, TNM stage, type of gastrectomy, tumor deposit, lymphovascular invasion, PNI, preoperative CA19-9 levels, and CEA levels were significant prognostic factors. Gastric cancer patients with PNI had a significantly lower 5-year OS rate than those without PNI (5- year OS: 38.3% versus 66.6%, P < 0.001). In the multivariate analysis, age, Borrmann type Ⅳ, TNM stage, curability, tumor deposit, and PNI were independent prognostic factors for this population cohort. The strata analysis revealed that PNI merely had a significant impact on OS in patients at stages Ⅰ, Ⅱ, and Ⅲa.

  Conclusions  PNI is an independent prognostic factor in patients with gastric cancer and can be used as a prognostic indicator for gastric cancer patients at stages Ⅰ, Ⅱ, and Ⅲa.