[Proposal of a new lymph node mapping system for pancreatic head cancer]

The Japanese Pancreatic Society published the 4th edition of the general guidelines for the study of pancreatic cancer (JPS guidelines) in 1993. The current JPS guidelines differ from the UICC classification of lymph nodes. Thirty-five lymph node stations are divided into three groups in the JPS guidelines. Group 1 (n1) corresponds closely with the regional lymph nodes in the UICC classification. Group 2 (n2) and group 3 (n3) are distant metastases in the UICC classification. To clarify practical lymph node mapping, 2,449 resected tubular adenocarcinomas of the pancreas head registered with the JPS were analyzed. Lymph node involvement was observed most frequently in posterior pancreatoduodenal (PPD) and anterior pancreatoduodenal (APD) and then in paraaortic (n2) nodes. Fifty-six patients who achieved 5-year survival were registered, of whom 19 had lymph node involvement. The sites of lymph node involvement were limited to the PPD and/or APD nodes in 14 cases. PPD and APD nodes differ from the other n1 in terms of high incidence of metastasis and fair prognosis. In conclusion, we propose a new practical lymph node mapping system in which PPD and APD nodes are the first station and the other n1 are the second station.