Intensity-modulated radiation therapy in the treatment of head and neck cancer involving the base of the skull.

Tumors invading the skull base pose a difficult problem for the treating radiation oncologist. When confronting these highly complex tumors where the gross tumor abuts the optic apparatus or brain stem, the physician often has to make a difficult choice regarding coverage of the tumor, i.e., underdosing portions of the tumor to protect the critical normal tissues versus accepting the risk of late complication while ensuring full coverage of the tumor. This situation is often encountered in advanced T4 disease originating either in the paranasal sinuses or the nasopharynx. In this case report, the author presents a case in which difficult decisions were made when treating a complex, locally advanced, T4 nasopharyngeal cancer that invaded the skull base.