Stage IV nasal cavity and ethmoid sinus cancer is divided into stages IVA, IVB, and IVC. In stage IVA, cancer (1) has spread to one lymph node on the same side of the neck as the cancer and the lymph node is larger than 3 centimeters but not larger than 6 centimeters; or to more than one lymph node on the same side of the neck as the original tumor and the lymph nodes are not larger than 6 centimeters; or to lymph nodes on the opposite side of the neck as the original tumor or on both sides of the neck, and the lymph nodes are not larger than 6 centimeters, and cancer has also spread to any of the following: the nasal cavity, ethmoid sinus, eye socket, maxillary sinus, roof of the mouth, and/or the bone between the eyes; or (2) has spread to any of the following: the front of the eye, skin of the nose or cheek, front parts of the skull, base of the skull, and/or the sphenoid or frontal sinuses, and cancer may also have spread to one or more lymph nodes 6 centimeters or smaller, anywhere in the neck. In stage IVB, cancer (1) has spread to any of the following: the back of the eye, brain, middle parts of the skull, nerves in the head that go to the brain, upper part of the throat behind the nose, and/or the base of the skull, and cancer may be found in one or more lymph nodes of any size, anywhere in the neck; or (2) is found in a lymph node larger than 6 centimeters. Cancer may also be found anywhere in or near the nasal cavity and ethmoid sinus. In stage IVC, cancer may be found anywhere in or near the nasal cavity and ethmoid sinus, may have spread to lymph nodes, and has spread to organs far away from the nasal cavity and ethmoid sinus, such as the lungs.