Stage IV is divided into stages IVA, IVB, and IVC. In stage IVA, cancer (1) has spread to cartilage around the thyroid or trachea, the bone under the tongue, the thyroid, or nearby soft tissue. Cancer may have spread to one lymph node on the same side of the neck as the tumor and the lymph node is 3 centimeters or smaller; or (2) has spread to one lymph node on the same side of the neck as the tumor (the lymph node is larger than 3 centimeters but not larger than 6 centimeters) or to lymph nodes anywhere in the neck (affected lymph nodes are 6 centimeters or smaller), and one of the following is true: (1) cancer is found in one area of the hypopharynx and/or is 2 centimeters or smaller; or (2) cancer is found in more than one area of the hypopharynx or in nearby tissues, or is larger than 2 centimeters but not larger than 4 centimeters and has not spread to the larynx (voice box); or (3) cancer has spread to the larynx or esophagus and is more than 4 centimeters; or (4) cancer has spread to cartilage around the thyroid or trachea, the bone under the tongue, the thyroid, or nearby soft tissue. In stage IVB, the tumor (1) has spread to muscles around the upper part of the spinal column, the carotid artery, or the lining of the chest cavity and may have spread to lymph nodes, which can be any size; or (2) may be any size and has spread to one or more lymph nodes that are larger than 6 centimeters. In stage IVC, the tumor may be any size and has spread beyond the hypopharynx to other parts of the body.