Cancer is either (1) 4 centimeters or smaller; cancer has 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) larger than 4 centimeters or has spread to the epiglottis (the flap that covers the trachea during swallowing). 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.