Objective: To evaluate the incidence and prognostic importance of micrometastatic disease in regional lymph nodes from Dukes' B colorectal carcinomas.
Design: Retrospective study.
Setting: University hospital, Sweden.
Subjects: 100 patients operated on for primary colorectal carcinoma, classified as Dukes' B lesions.
Interventions: The regional lymph nodes were re-examined immunohistochemically using monoclonal antibodies against cytokeratin.
Outcome measures: Incidence and prognostic importance of micrometastases.
Results: Micrometastases were found in 39% (39/100) of the patients. The number of positive cells in the lymph nodes examined varied from 1 to over 100. They appeared as single cells or small clusters of cells located within the capsule or in the peripheral sinus of the lymph node. At least three sections from each of three lymph nodes had to be examined to identify 95% of the patients with lymph node micrometastases. The outcome of the patients with micrometastases was not significantly different from that of patients with no epithelial cells in the lymph nodes.
Conclusion: Micrometastases in regional lymph nodes are a interesting phenomenon but clinically seem to be of only weak prognostic value.