The Poor Prognosis of Patients with Stage III Gastric Cancer after D2 Dissection Is Mainly due to Lymphatic Metastasis, Especially the Metastasis of No.12a LN: A Nested Case-Control Study

Abstract

Background: The prognosis of stage III gastric cancer (GC) patients based on the 8th edition TNM staging system after D2 dissection was still heterogeneous. We aimed to explore clinicopathological reasons that led to the poor prognosis of these patients, especially from a surgical aspect. Methods: We divided 320 stage III GC patients who underwent distal or total gastrectomy with D2 lymphadenectomy into group 1 and group 2, according to the disease-free survival (DFS), and compared the clinicopathological features between these 2 groups. Then, we divided group 1 into group 1D and group 1T and group 2 into group 2D and group 2T, according to distal or total gastrectomy. Finally, we compared the status of lymph node (LN) metastasis in each group of perigastric LN between the subgroups, respectively. Results: Univariate analyses revealed that patients’ LN metastasis was the only significant difference between group 1 and group 2 (p < 0.05). Compared with group 1D, the percentage of patients who had metastatic LN in all groups of the perigastric LN (included No.1, 3, 4sb, 4d, 5, 6, 7, 8a, 9, 11p and 12a) increased in group 2D. A similar tendency was found in group 2T (included No.1, 2, 3, 4sa, 4sb, 4d, 5, 6, 7, 8a, 9, 10, 11p, 11d and 12a) compared with group 1T. Further multivariate regression analyses revealed that the increases of group No.12a and 5 LN were significant (p < 0.05) in group 2D, the increases of group No.12a, 8a and 6 LN were significant (p < 0.05) in group 2T, respectively. Among these, the increases of group No.12a LNs were the most significant (p < 0.01). Conclusions: The poor prognosis of patients with stage III GC after D2 dissection is mainly due to lymphatic metastasis. The status of LN metastasis in the prognostic value of GC needs to be further enhanced in present staging systems. Maybe the metastasis of No.12a LN is the most significant poor prognostic factor of these patients. It points out that the dissection of No.12a LN should be carefully performed in radical gastrectomy.