The Prognostic Significance of Immunohistochemically Detected Isolated Tumor Cells in Lymph Node in Colorectal Cancer

Purpose: Metastasis of a colorectal carcinoma to regional lymph nodes indicates poor prognosis. The detection of lymph node metastasis is routinely performed by histopathological analysis of hematoxylin-eosin (H&E) stained sections. However the routine histological technique may fail to detect isolated tumor cells in lymph nodes. The aims of this study are to elucidate the prognostic significance of the presence of isolated tumor cells in the regional lymph nodes in colorectal cancer, and to elucidate the correlation between the presence of isolated tumor cells and p53 protein expression in the primary colorectal cancer tissue. Methods: We used immunohistochemical staining with anti-cytokeratin antibody to examine 452 lymph nodes in 24 patients (11 recurrent and 13 nonrecurrent) who were histologically determined Astler-Coller B. And we used immunohistochemical staining with p53 protein to examine primary colorectal cancer tissues of the patients. Results: Immunohistochemical staining of cytokeratin revealed the presence of isolated tumor cells in 5/13 patients (38.5%), 5/214 lymph nodes (2.34%) in the nonrecurrent group and 6/11 patients (54.6%), 11/244 lymph nodes (4.51%) in the recurrent group, respectively. The detection rate of isolated tumor cells in the recurrent group was slightly higher than nonrecurrent group, but the difference was not significant statistically. The expression rate of p53 protein was 23.1% (3/13) in the nonrecurrent group and 36.4% (4/11) in the recurrent group, respectively. The expression rate of the p53 protein was not significantly correlated with the presence of isolated tumor cells in regional lymph nodes and the rate of tumor recurrence. Conclusions: The presence of isolated tumor cells in regional lymph nodes was not a prognostic indicator in predicting recurrence in histologically determined Astler-Collar B colorectal cancer patients.