Analysis of clinical characteristics and prognosis of perineural invasion in patients with gastric carcinoma

Objective To investigate the association between perineural invasion (PNI) and clinicopathological factors and the effect of PNI on overall survival in patients with gastric carcinoma.Methods A total of 178 patients with gastric carcinoma from January 2004 to May 2008 were analyzed retrospectively. Paraffin sections of surgical specimens from all the patients who underwent gastric resection were stained with laminin. PNl-positive was defined as infiltration of carcinoma cells into the perineurium or neural fascicles. The association of PNI with clinicopathologic features and prognosis of gastric carcinoma was studied. Results PNI was positive in 78 of 178 patients (43.8%). The proportions of T stage, lymph node metastasis and TNM stage were significantly higher in PNI-positive group than those in PNl-negative group (all P＜0.01 ). The PNI positive rate was correlated with the depth of gastric mural invasion and clinical stage. The overall survival in PNI-positive group was significantly lower than that in PNI-negative group by univariate analysis (P＜0.01). The mean survival of PNI-positive patients (28.6 months) was significantly shorter than that of PNI-negative patients (44.3 months,P＜0.01), which was also influenced by pN stage, pT stage, and clinical stage(P＜0.0l ). By multivariable Cox proportional hazards model of overall survival, the positivity of PNI appeared to be an independent prognostic factor (hazards ratio=2.257,95% CI: 1.268-4.019, P=0.006).Conclusions PNI is associated with the degree of malignancy in gastric cancer. PNI can be a candidate of new prognostic factor. Key words: Stomach neoplasms;  Perineural invasion;  Prognosis