Definition

One of the following is true: (1) one or more lymph nodes with cancer that is HPV p16-positive are found but the place where the cancer began is not known. The lymph nodes with cancer are 6 centimeters or smaller, on one side of the neck; or (2) cancer is found in the oropharynx (throat) and the tumor is 4 centimeters or smaller. Cancer may have spread to one or more lymph nodes that are 6 centimeters or smaller, on the same side of the neck as the primary tumor.