Venous Invasion and Perineural Invasion as Upstaging and Poor Prognostic Factors in N0 Gastric Cancers

Background/Aim: Lymph node metastasis is an important prognostic factor in gastric cancer patients. In node negative (N0) gastric cancer patients, additional prognostic factors are needed to reinforce TNM staging. Patients and Methods: We semi-quantitatively recorded the presence of lymphatic, venous, and perineural invasion and evaluated the possibility that they could be used as upstaging factors in N0 gastric cancer by comparing N0 gastric cancer cases with N1 cases. Results: Venous (p<0.001) and perineural (p<0.001) invasion were important factors in the relapse-free survival of N0 patients, but lymphatic invasion was not. N0 cases with venous or perineural invasion had survival curves similar to those of N1 patients. In addition, the number of invasive features (lymphatic, venous, or perineural) was an important factor in predicting poor patient survival. Conclusion: Venous and perineural invasion were significant prognostic factors in N0 gastric cancer cases. It is necessary to record lymphatic, venous, and perineural invasion separately in the pathology report, especially in cases of N0 gastric cancer.