tumor cells are few and only easily recognized by careful examination or by using techniques such as special stains, i.e. immunohistochemical. When the sentinel node is free of tumor cells, this is highly predictive of freedom from metastasis in the entire lymphatic basin, thus allowing a full node dissection to be avoided. The practice of sentinel lymph node mapping has changed the surgical approach in many cancer systems, sparing a formal lymph node dissection for patients with sentinel lymph node negative for tumor and directing a full node dissection for patients with sentinel lymph node positive for tumor metastases. For example, in stage II breast carcinoma, using the sentinel lymph node technique, 65% of patients could be spared from a formal node dissection. Complications Lymphedema may result from lymphadenectomy. Extensive resection of lymphatic tissue can lead to the formation of a lymphocele. It is uncertain whether inserting wound drainage after groin lymph nodes dissection can reduce complications such as seroma, haematoma, wound dehiscence, and wound infection. See also List of surgeries by type References External links Axillary Lymph Node Dissection - online learning resource Surgical oncology Lymphatic organ surgery