Source:http://linkedlifedata.com/resource/umls/id/C0862719
NCI: Stage IV is divided into stage IVA, stage IVB, and stage IVC. In stage IVA, (1) cancer has spread through the thyroid cartilage and/or has spread to tissues beyond the larynx, such as the neck, trachea, thyroid, or esophagus; cancer may have spread to one lymph node on the same side of the neck as the original tumor and the lymph node is 3 centimeters or smaller; or (2) cancer has spread to one lymph node on the same side of the neck as the original tumor and the lymph node is larger than 3 centimeters but not larger than 6 centimeters, or has spread to more than one lymph node anywhere in the neck with none larger than 6 centimeters; cancer may have spread to tissues beyond the larynx, such as the neck, trachea, thyroid, or esophagus. The vocal cords may not move normally. In stage IVB, (1) cancer has spread to the space in front of the spinal column, surrounds the carotid artery, or has spread to parts of the chest; cancer may have spread to one or more lymph nodes anywhere in the neck and the lymph no