Occurrence and prognostic importance of micrometastases in regional lymph nodes in Dukes' B colorectal carcinoma: an immunohistochemical study.

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.