Metastatic patterns and surgical methods for lymph nodes No. 5 and No. 6 in proximal gastric cancer

Objective The current surgical treatment guidelines for early proximal gastric cancer (PGC) still lack agreement. Lymphadenectomy of lymph nodes No. 5 and No. 6 is the major difference between total and proximal gastrectomy. We elucidated the appropriate surgical procedure for PGC by investigating the pathological characteristics and prognostic significance of lymph nodes No. 5 and No. 6. Methods In total, 333 PGC patients who underwent total gastrectomy were enrolled in this study. We investigated their clinicopathological characteristics and the metastatic patterns of the lymph nodes. Patients with metastasis in lymph nodes No. 5 and No. 6 were combined into one group and we compared the difference in survival between those with and without metastasis in lymph nodes No. 5, 6 (lymph nodes No. 5 and No. 6 in any group of metastasis) for different subgroups. Results The metastatic rates for lymph nodes No. 5 and No. 6 in PGC were 9.91% and 16.11%, respectively. The metastatic rate for both lymph nodes No. 5, 6 was 20.42%. Multivariate analysis showed that positive metastasis in lymph node No. 4, depth of invasion, and tumor size were independently correlated with the presence of metastasis in lymph nodes No. 5, 6. Conclusions When lymph node No. 4 is positive (intraoperative pathology) or tumor size ≥5 cm or T4 stage, lymphadenectomy should be performed for lymph nodes No. 5 and No. 6, and total gastrectomy is recommended.