Practical grouping of positive lymph nodes in pancreatic head cancer treated by an extended pancreatectomy

Background. Until recently long-term survival has not been expected when at least one positive node was detected at any site in pancreatic head cancer treated by conventional pancreatectomy. However, even when nodal involvement is seen, there has been an increasing number of long-term survivors after extended pancreatectomy in which a wide range of lymphatic and connective tissues were cleared. 1 Thus the purpose of the present study was to establish a practical rational grouping of positive lymph nodes in pancreatic head cancer treated by extended pancreatectomy. Methods. In 81 patients who tolerated extended pancreatectomy for cancer of the pancreatic head, a mean of 56 ± 23 (range, 28 to 89) lymph nodes in each patient were examined under a microscope to determine the presence or absence of cancer. They were classified anatomically into 14 lymph node groups, and the incidence, distribution, and number of positive nodes were examined. A simplified grouping was made on the basis of the histologic findings and was checked against long-term survival rates. Results. Nodal involvement was detected in 59 (73%) of 81 patients, and positive nodes were more commonly observed in the posterior pancreaticoduodenal (PPD), superior mesenteric (SM), and anterior pancreaticoduodenal (APD) groups than in the 11 other groups (p < 0.05). The PPD, APD, and SM groups offered the sole sites of nodal involvement with incidence levels of 23%, 17%, and 6%, respectively, whereas none of the 11 other groups did. Thus patients were classified into four groups: (a), negative in all 14 lymph node groups (n = 22); (b), positive but limited to the PPD/APD groups (n = 14); (c), also positive in the SM group, but negative in the 11 other groups (n = 13); and (d), also positive in at least one of the 11 other groups (n = 32). This classification was associated well with the 5-year survival rate: 59% in group (a), 53% in group (b), 15% in group (c), and 0% in group (d) [p < 0.05; group (b) versus group (c)]. Also this grouping associated well with the total number of positive nodes (p < 0.05). The 5-year survival rate in patients with one to three positive nodes was 47% and was more than 6% in patients with four to seven positive nodes (p < 0.05). Conclusions. In the clinicopathologic staging of the lymphatic spread from carcinoma of the pancreatic head, the PPD and APD groups were considered the first stations of lymphatic metastasis, whereas the 12 other groups—including the SM group—wer