The purpose of this study is to investigate perineural invasion (PNI) as a prognostic factor in gastric cancer patients. 455 patients submitted to extended (D2 or more) lymphadenectomy (median number of 39 retrieved lymph nodes, range: 15-140) between 1995 and 2012 were retrospectively studied. Patients were categorized in two groups according to the PNI status, and PNI positivity was assessed in presence of cancer cells in the perinerium or the neural fascicles using hematoxylin and eosin staining. Median follow-up for surviving patients was 80.3 months. Survival analysis was performed by univariate and multivariate analysis, using a Cox proportional hazards model. 162 patients (33.9%) had positive PNI; this was strongly associated with advanced stages of disease, residual tumor, lymphovascular invasion, Lauren diffuse-mixed histotype and tumor size. Five-year cancer-related survival was 65,7% and 20,6% in PNI negative vs. positive groups, respectively (p < 0.001). The prognostic impact of PNI at univariate analysis was particularly evident in patients submitted to R0 surgery, early as well as advanced stage, advanced nodal stage and T status. At multivariate analysis, PNI did not result statistically significant in the overall series, but emerged as an independent prognostic factor in the group of patients with Lauren intestinal histotype (p = 0.005, hazard ratio: 1.99, 95% confidence interval 1.24-3.19). PNI is related to advanced stage and poor long-term survival in gastric cancer, and may serve as an adjunctive prognostic factor in the intestinal histotype.

The extent of lymphadenectomy in gastric cancer (GC) surgery has been for long time a matter of debate. Randomized trials performed in the West reported worse results of D2 dissection, in terms of postoperative complications and long-term survival benefit, than Eastern series and observational studies from specialized Western centers. However, long-term re-evaluation of such trials and in depth-analysis of other experiences demonstrated the potential benefit of D2 in reducing the probability of cancer-related death and the safety of this procedure when avoiding unnecessary spleno-pancreatectomy and in centers with ad adequate surgical volume. Nowadays, the D2 is considered the standard treatment in most guidelines all over the world. More limited procedures (D1, D1 plus) may be adequate in selected cases, and more extended dissections (D2 plus) could be indicated in advanced forms with high risk of metastases to distant nodes, but in specialized centers or in the setting of clinical studies. The integration with neoadjuvant therapies and multimodality approach could offer a chance of cure in groups of patients with poor results when approached with standard treatment.

No abstract

No abstract