Pattern of No. 12a lymph node metastasis in gastric cancer

Objective: The current standard D2 lymphadenectomy for gastric cancer (GC) includes dissection of lymph nodes (LNs) along the proper hepatic artery (No. 12a), however, the survival benefit remains controversial. The purpose of this study was to evaluate the pattern of No. 12a LN metastasis (LNM) in GC and explore the indications for No. 12a LN dissection. Methods: Medical records of 413 consecutive GC patients who underwent curative surgery in Zhongshan Hospital, Fudan University between January 2015 and December 2018 were enrolled and reviewed retrospectively. The correlation between No. 12a LNM and clinicopathologic characteristics of patients was analyzed. Results: The overall incidence of No. 12a LNM was 2.67% (11/413). Tumor location (P=0.012), depth of tumor infiltration (P<0.01) and N stage (P=0.018) were significant factors associated with No. 12a LNM. All the tumors with No. 12a LNM involved the lower third of the stomach and were in T3-4 stages. Patients with No. 12a LNM had extensive LNM than those without (20.91 +/- 4.25 vs. 5.0 +/- 0.54, P<0.001). For advanced GC patients (stage III/W) with tumors involving the lower third of the stomach, the incidence of No. 12a LNM increased to 10.7% (11/103). Patients with No. 12a LNM had a significantly poorer recurrence-free survival (RFS) (P=0.005) and overall survival (OS) (P=0.017). According to the result of multivariable Cox regression, No. 12a LNM was not an independent impact factor on RFS and OS. Conclusion: The overall incidence of No. 12a LNM was low but it was much higher in GC patients who had very advanced tumors involving the lower third of the stomach. No. 12a LN dissection should be considered for these patients to improve the survival outcomes.