Stage IVB includes: (T4b, Any N, M0); (Any T, N3, M0). T4b: Very advanced disease. Tumor invades skull base and/or pterygoid plates and/or encases carotid artery. N3: Metastasis in a lymph node, more than 6 cm in greatest dimension. M0: No distant metastasis. (AJCC 7th ed.) [from
NCI]