The Necessity of Dissection of No. 14 Lymph Nodes to Patients With Pancreatic Ductal Adenocarcinoma Based on the Embryonic Development of the Head of the Pancreas

Abstract

Objectives: Pancreaticoduodenectomy (PD) followed by lymphadenectomy is performed for patients with pancreatic ductal adenocarcinoma (PDAC) located in the head of the pancreas. Because the head of the pancreas could be divided into dorsal or ventral primordium in relation to embryonic development, the metastasis of lymph node (LN) may differ. In this retrospective study, we evaluated the impact of extended or standard LN dissection for PDAC located in ventral or dorsal primordia of the pancreatic head. Methods: From February 2016 to November 2018, 178 patients who underwent PD for PDAC were enrolled at the Pancreatic Disease Center, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University. According to the tumor location and the range of LN dissection, all patients were divided into three groups: ventral primordium with extended lymphadenectomy (VE group), ventral primordium with standard lymphadenectomy (VS group), and dorsal primordium with extended lymphadenectomy (DE group). Clinical and pathological features were retrospectively analyzed as were the long-term survival outcomes. Results: More patients in the VE group were detected with metastasis in the lymph nodes around the superior mesenteric artery (LN14) than those in the DE group (LN along the right side of the superior mesenteric artery, LN14ab): 22.9 vs. 5.9%, p = 0.005; (LN along the left side of the superior mesenteric artery, LN14cd): 10.0 vs. 0.0%, p = 0.022. LN14 was involved in more patients in the VE group than in the VS group (22.9 vs. 5.0%, p = 0.015). For IIb-stage patients in the VE group, the overall survival time (18.3 vs. 9.3 months, p < 0.001) and disease-free survival time (12.2 vs. 5.1 months, p = 0.045) were longer in those with LN14cd (-) than those with LN14cd (+). Conclusion: This study suggested that patients with PDAC located in the ventral head of the pancreas had higher risk of LN14 involvement compared with those at dorsal. Thus, a thorough dissection of LN14 in PDAC located in the ventral head of the pancreas is recommended to optimize the regional extended lymphadenectomy.

Keywords: lymph node dissection (LN dissection); lymph nodes around superior mesenteric artery (SMA); pancreas head cancer; pancreatic ductal adenocarcinoma (PDAC); pancreatic embryology.

Figure 1

(A) Sagittal view. (B) Coronary view. The pancreas is codeveloped from the ventral and dorsal primordium, which mainly constitute the body and tail of the pancreas and anterior partial head of the pancreas (yellow). The ventral primordium develops into the posterior part of the head of the pancreas that surrounds SMA/SMV. The head of the pancreas was divided into the ventral and dorsal pancreatic head by the line that links the portal vein (PV)/superior mesenteric vein (SMV) and anterior edge of the intrapancreatic bile duct. The main pancreatic duct of the common bile duct was located in the ventral pancreatic head, and the accessory pancreatic duct was located in the dorsal pancreatic head. CBD Common Bile Duct MPD Main Pancreatic Duct SMA Superior Mesenteric Artery SMV Superior Mesenteric Vein DP Dorsal Primordium VP Ventral Primordium.

Figure 2

A dotted line on the CT image indicates the boundary between the ventral and dorsal head of the pancreas in (A,B). (A) DE group: tumor located in the dorsal head of the pancreas. CBD, common bile duct. PV portal vein. Arrows indicate the tumor. (B) VE and VS groups: tumor located in the ventral head of the pancreas. MPD, mean pancreatic duct. Arrows indicate the tumor.

Figure 3

Standard lymphadenectomy. No. 5 Supra pyloric lymph nodes; No. 6 infra pyloric lymph nodes; No. 8a lymph nodes in the anterosuperior group along the common hepatic artery No. 12b lymph nodes along the bile duct; No. 12c (located next to 12b), lymph nodes around the cystic duct; No. 13a lymph nodes on the posterior aspect of the superior portion of the head of the pancreas; No. 13b lymph nodes on the posterior aspect of the inferior portion of the head of the pancreas; No. 14a-b lymph nodes along right side of superior mesenteric artery No. 17a lymph nodes on the anterior surface of the superior portion of the head of the pancreas; No. 17b lymph nodes on the anterior surface of the inferior portion of the head of the pancreas. Extended lymphadenectomy. No. 8p lymph nodes in the posterior group along the common hepatic artery; No. 12a lymph nodes along the hepatic artery; No. 12p lymph nodes along the portal vein; No. 14c-d lymph nodes along the left side of superior mesenteric artery; No. 16 lymph nodes around the abdominal aorta besides standard range of lymph node dissection.

Figure 4

Flow chart of inclusion: DE patients with tumor located in the dorsal head of the pancreas performed with extended lymphadenectomy; VE patients with tumor located in the ventral head of the pancreas performed with extended lymphadenectomy; VS patients with tumor located in the ventral head of the pancreas performed with standard lymphadenectomy.

Figure 5

(A) Survival curve of subgroup (patients with IIb stage including LN(+) by direct tumor extension in VE group) according to the LN14cd (±), mOS median overall survival (B) Disease-free survival curve of subgroup (patients with IIb stage including LN(+) by direct tumor extension in VE group) according to the LN14cd (±), mDFS median disease-free survival.