Significance of lymph node micrometastasis in pN0 hilar bile duct carcinoma

Aims To examine micrometastasis in node-negative hilar bile duct carcinoma (HBDC) using an immunohistochemical method and evaluated the clinical significance. Methods Four hundred and twenty three regional lymph nodes from 28 patients with node-negative HBDC who had undergone a resection were immunostained with an antibody against cytokeratins eight and 18 (CAM 5.2). Results Lymph node micrometastasis was detected in 11 of the 28 patients and 14 of the 423 lymph nodes. Lymph node micrometastasis was significantly correlated with the pT classification (p=0.03), the histopathological grading (p=0.01) and venous invasion (p=0.05). The 5-year survival rate of the patients with lymph node micrometastasis was 21.8%, as opposed to 66.5% in the patients without micrometastasis. Patients with micrometastasis showed a significantly poorer survival rate than those without micrometastasis (p=0.02). Conclusion The results suggest that immunohistochemically detected lymph node micrometastasis has an impact on the outcome in HBDC.