Clinical Significance of Lymph Node Micrometastasis in Dukes' Stage A&B Colorectal Cancer: An Immunohistochemical Study

ABSTRACT

PURPOSE: Lymph node metastasis is the most important prognostic factor in colorectal cancer. However, 20~30% of patients with lymph node negative colorectal cancer die of recurrent disease. We investigated whether the detection of micrometastasis is of any clinical significance in Dukes' stage A & B colorectal cancer. METHODS: Ninety patients who underwent curative resection of colorectal cancer from Aug. of 1996 to Jan. of 1999 were entered the study. For examination, we used paraffin blocks of lymph nodes which were metastasis-free by conventional histopathology. After preparation of tissue blocks using the serial sectioning technique, the specimens were stained with immunohistochemical method using anticytokeratin antibody. And the hematoxylin-eosin staining was repeated. RESULTS: We disclosed micrometastases in 15 of 90 cases, mostly located in subcapsular sinuses. And in 8 of 15 cases, we also found metastases in repeated H&E staining. There were no significant relationship between the detection of micrometastases and the depth of wall invasion, the histological grade and the status of lymphovascular invasion. With median follow-up of 15 months, we found no significant difference in recurrence between the micrometasis positive and negative groups. CONCLUSIONS: The result showed that the micrometastasis of lymph node in colorectal caner might increase the risk for development of tumor recurrence. But because of small numbers of recurrent cases and relatively short follow-up period, there was no statistically significant relationship between micrometastasis negative and positive groups.