Lymph Node Micrometastases and Isolated Tumor Cells Influence Survival in Stage I and II Colon Cancer

PURPOSE: Lymph-node status is considered the most important prognostic factor in colorectal cancer. The aim of the present prospective study was to evaluate the influence of micrometastases and isolated tumor cells on recurrence and disease-free survival in colon cancer. METHODS: A total of 193 patients with colon cancer, operated on between 2000 and 2005, were enrolled in the study. All lymph nodes were examined by routine microscopy in hematoxylin and eosin-stained sections. If no metastases were identified in any node, all nodes were examined immunohistochemically with monoclonal antibody CAM 5.2. RESULTS: Ordinary metastases were found in 67 patients, leaving 126 patients in stage I/II. Immunohistochemistry showed that 5% (6/126) of these had micrometastases and 26% (33/126) had isolated tumor cells. A median of 5 years of follow-up revealed local or distant recurrence in 23% (9/39) of stage I/II patients with micrometastases or isolated tumor cells, compared with 7% (6/87) without micrometastases or isolated tumor cells (P = .010). Five-year disease-free survival for patients with and without micrometastases or isolated tumor cells was 75% and 93%, respectively (P = .012). When analyzed separately, patients with isolated tumor cells (excluding micrometastases) had also lower survival than node-negative patients (P = .012). CONCLUSION: The presence of micrometastases and isolated tumor cells was found to be a prognostic factor for recurrence and disease-free survival. This may have implications for future treatment of stage I/II colon cancer.