Lymphatic flow in carcinoma of the head of the pancreas.

The lymphatic pathway from the head of the pancreas to the para-aortic lymph nodes was examined on the basis of the frequency of lymph node involvements. Forty-four patients were examined. All patients had extended radical operations. Thirty-one of 44 (70.5%) patients had lymph node involvement. The lymph nodes that had a high metastatic rate included the following: (1) lymph nodes around the common hepatic artery (number 8 lymph node); (2) lymph nodes of the hepatoduodenal ligament (number 12 lymph node); (3) the posterior pancreaticoduodenal lymph node (number 13 lymph node); (4) lymph nodes around the superior mesenteric artery (number 14 lymph node); (5) para-aortic lymph nodes (number 16 lymph node); and (6) the anterior pancreaticoduodenal lymph node (number 17 lymph node). Twenty-eight of these 31 patients had disease in the posterior pancreaticoduodenal lymph node. The patterns of lymph node involvement consisted of four combinations: number 13-number 17, number 13-number 14, number 14-number 16, and number 17-number 8. All of the patients with number 16 nodal involvement had number 14 lymph node metastasis. However, there was no relationship between tumor size and lymph node involvement. Based on these results, the main lymphatic pathway from the head of the pancreas to the para-aortic lymph nodes was thought to be via the lymph nodes around the superior mesenteric artery, assuming that lymphatic flow is anterograde. In addition, this study demonstrates that it is necessary to perform an extensive lymph node dissection, including the para-aortic lymph node, even in patients with small tumors.