 Failure to detect cancer cells in the sentinel node can lead to a false negative result—there may still be cancerous cells in the lymph node basin.In addition, there is no compelling evidence that patients who have a full lymph node dissection as a result of a positive sentinel lymph node result have improved survival compared to those who do not have a full dissection until later in their disease, when the lymph nodes can be felt by a physician.Such patients may be having an unnecessary full dissection, with the attendant risk of lymphedema.