Factors associated with metastasis in superior mesenteric vein lymph node in subtotal gastrectomy for gastric cancer: Retrospective case control study.

Objective: The revised Japanese treatment guideline for gastric cancer recommends dissection of the superior mesenteric vein lymph node (No. 14v LN) if there is metastasis in infrapyloric lymph node (No. 6 LN). However, it is still controversial whether LN dissection is necessary. The aim of this study was to investigate the factors associated with metastasis in No. 14v LN. Methods: Patients who underwent D2 lymphadenectomy between 2003 and 2010 were included. We excluded patients who underwent total gastrectomy, had multiple lesions, or had missing data about the status of metastasis in the LNs that were included in D2 lymphadenectomy. Clinicopathologic characteristics and the metastasis in regional LNs were compared between patients with No. 14v LN metastasis (14v+) and those without (14v-). Results: Five hundred sixty patients were included in this study. Univariate analysis showed that old age, larger tumor size, tumor location, differentiation, lymphatic invasion, venous invasion, perineural invasion, T classification, and N classification were related to metastasis in No. 14v LN. Multivariate analysis showed differentiation (P=0.027) and N classification (P<0.001) were independent related factors. Metastasis in infrapyloric lymph node (No. 6 LN) and proxiaml splenic lymph node (No. 11p LN) was independently associated with metastasis in No. 14v LN. Conclusions: Differentiation and N classification were independent factors associated with No. 14v LN metastasis, and No. 6 and No. 11p LN metastasis were independent risk factors for No. 14v LN metastasis.