Wächterlymphknoten (engl. sentinel lymph node): Also referred to as "Sentinel-Lymphknoten". The sentinel lymph node is a a concept for the detection and treatment of metastasising cancer, particularly breast cancer. It is the first lymph node that is the target of metastasising cancer cells from the primary tumour. It is assumed that if the sentinel lymph node does not contain cancer cells, then there is a high likelihood the primary tumour has not yet spread to any other lymph nodes or other organs in the body.