Immunohistochemical detection of lymph node micrometastases from gallbladder carcinoma using monoclonal anticytokeratin antibody.

Abstract

The objective of this study was to define the sensitivity and clinical implications of the immunohistochemical detection of lymph node micrometastases in patients with gallbladder carcinoma (GBC). The authors examined a total of 385 regional lymph nodes taken from 26 consecutive patients with GBC who had undergone a radical resection. Histologic sections of the primary tumor and regional lymph nodes in each case were stained with both hematoxylin and eosin and an antibody against cytokeratins 8 and 18 (CAM5.2). A "micrometastasis" was defined as a metastasis missed on routine histologic examination with hematoxylin and eosin but detected by immunohistochemical examination with CAM5.2. Survival rates were calculated only in patients with Stage II or more advanced stage disease. All primary tumors were positive for CAM5.2. Routine histologic examination revealed 53 positive lymph nodes that were stained consistently with CAM5.2. Another seven lymph nodes had micrometastases. Patients with micrometastases showed a significantly worse survival rate than those without micrometastases (P = 0.037, log rank test). Among patients with no lymph node disease on routine histologic examination, there was a trend toward a worse survival rate in those with lymph node micrometastases (P = 0.10, log rank test). The paraaortic lymph nodes were involved more frequently in patients with lymph node micrometastases than those without (P = 0.009, Fisher exact test). The immunohistochemical detection of lymph node micrometastases using CAM5.2 is feasible in GBC patients and is useful in predicting survival in patients undergoing radical resection. Lymph node micrometastases may be an indicator of widespread lymph node disease in patients with GBC.