[Lymph node staging in gastrointestinal cancer. Combination of methylene blue-assisted lymph node dissection and ex vivo sentinel lymph node mapping].

The histopathological lymph node staging is of crucial importance for the prognosis estimation and therapy stratification in gastrointestinal cancer. However, the recommended numbers of lymph nodes that should be evaluated are often not reached in routine practice. Methylene blue assisted lymph node dissection was introduced as a new, simple and efficient technique to improve lymph node harvest in gastrointestinal cancer. This method is inexpensive, causes no delay and needs no toxic substances. All studies performed revealed a highly significantly improved lymph node harvest in comparison to the conventional technique. Moreover, this technique can be combined with a new ex vivo sentinel lymph node mapping that for the first time is based on histological sentinel lymph node detection. The success rate of this method is similar to conventional techniques and it enables an efficient application of extended investigation methods, such as immunohistochemistry or the polymerase chain reaction.