Implication of Micrometastases of Lymph Nodes in Patients With Extended Operation for Pancreatic Cancer

Introduction Accurate evaluation of lymph node metastases is very important in planning treatment for pancreatic cancer. Aim To detect micrometastases in lymph nodes dissected from patients with pancreatic cancer. Methodology We used cytokeratin staining of negative lymph nodes in routine hematoxylin–eosin (HE) staining. We examined by cytokeratin staining 239 HE-negative nodes from 7 patients with no pathologic evidence of lymph node metastasis (n0 cases) and 718 HE-negative group 2 nodes from 23 patients with metastasis in group 1 lymph nodes (n1 cases) who underwent extended operation combined with intraoperative radiation therapy (IORT). Results Cytokeratin staining identified 15 positive nodes among the 239 HE-negative nodes from the 7 n0 cases and 8 positive nodes among the 718 HE-negative nodes from the 23 n1 cases. Among the 7 n0 cases, 5 (71.4%) had positive n1 nodes and 2 (28.3%) also had positive n2 nodes. Among the 23 n1 cases, 4 (17.4%) had positive n2 nodes. Patients with micrometastases in n2 nodes died within 25 months. Conclusion Cytokeratin staining is very useful to evaluate the involvement of lymph nodes in pancreatic cancer. Prognosis of pancreatic cancer should be determined in conjunction with evaluation of nodal status by cytokeratin staining. Extended operation was not useful for pancreatic cancer patients with micrometastases of group 2 nodes.