Clinical Implications of Lymph Node Micrometastases in Patients with Colorectal Cancers

There is no unanimity about the prognostic significance of lymph node micrometastases from colorectal cancer. A case-control study of patients with recurrent and nonrecurrent colorectal cancer who were closely matched for the Dukes stage, extent of lymph node dissection, tumor size, tumor location, number of resected lymph nodes, age and gender was performed. The presence of micrometastases in a total of 1,633 lymph nodes from 44 patients (22 with and 22 without recurrence) were examined by immunohistochemistry using antibodies for cytokeratin (KL-1) and p53 (RSP53). Immunostaining with KL-1 revealed micrometastases in 15/22 patients [68%; 82/820 lymph nodes (10%)] and 15/22 patients [68%; 45/813 lymph nodes (6%)] in the recurrent and nonrecurrent groups, respectively. Immunohistochemical analysis, using RSP53, of 18 paired patients with p53-positive primary tumor revealed micrometastases in 4/9 patients [44%; (7/265 lymph nodes (2.6%)] and 4/9 patients [44%; 6/257 lymph nodes (2.3%)] with and without recurrence, respectively. Neither the micrometastatic frequencies of the patients nor the resected lymph nodes of the recurrent and nonrecurrent groups differed significantly. Micrometastases in regional lymph nodes are an interesting phenomenon, but do not influence patients' prognoses if the involved lymph nodes are removed.