Table 2.

The invaded structures classified by the difficulty of surgical resection

Category	Invaded structures	ENPG	IMRT	P value
Easily resectable tumors	Confined to base wall of the sphenoid sinus	19	29	0.612
	Superficial clivus	21	30
	Ethmoid sinus	11	7
	Maxillary sinus	3	4
	Pterygoid structures	38	46
Potentially resectable tumors	Beyond base wall of the sphenoid sinus	18	21	0.431
	Inner table of the clivus	17	14
	Petrous apex	30	41
	ICA	14	23
	Meninges	6	8
	Cavernous sinus	17	24
	Non-functional brain area	3	1
	Orbit	7	2
	Optic nerve	3	2

Pterygoid structures including medial/lateral plate of pterygoid process, root of pterygoid process, maxillary fissure of pterygoid process, and pterygopalatine fossa; ICA Internal Carotid Artery