Stage I includes: T1, N0, M0. T1: Maxillary sinus: Tumor limited to the maxillary sinus mucosa with no erosion or destruction of bone. Nasal cavity and ethmoid sinus: Tumor restricted to any one subsite, with or without bony invasion. N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 6th and 7th eds.) [from
NCI]