Preoperative lymph-node staging in gastrointestinal cancer--correlation between size and tumor stage

Our data suggest that lymph-node size is not a reliable indicator for lymph-node metastasis in gastric, esophageal, and colon cancer. Despite a significant difference in diameter of metastatic and non-metastatic nodes, the accurate evaluation of lymph-node metastasis in gastro-intestinal carcinoma cannot be determined by nodal size, because the majority of counted lymph nodes is ?5 mm and the frequency of small lymph-node metastases is high. Therefore imaging techniques using the size as criterion of nodal infiltration can not exactly assess the nodal status of patients with gastro-intestinal carcinomas. For rational lymphadenectomy, the value of sentinel node biopsy in gastro-intestinal cancer is now discussed. At the moment it is too early to apply sentinel node biopsy in order to reduce the extent of lymphadenectomy in these carcinomas [11]. Recent interest has focused on PET scanning in the detection of lymph-node metastases. PET represents a potentially ideal imaging modality for malignancy. It allows a quick and simultaneous assessment of both local and distant sites and, as a result of avid uptake of the glucose moiety, may potentially identify small tumor loads. There are only limited experience in detecting lymph-node metastases in gastro-intestinal carcinoma and the results of the published reports are controversially discussed [12, 13]. Our data demonstrate a high frequency of small lymph-node metastases in gastro-intestinal carcinoma and suggest that a careful histological search for small lymph-node metastases should be undertaken to avoid false-negative lymph-node staging. These results emphasize that a reliable pathological staging of gastro-intestinal cancer must be based on a standardized systematic lymphadenectomy because lymph-node sampling based on lymph-node size is not sufficient.