Cancer of the External Auditory Canal with Extensive Osteoradionecrosis of the Skull Base after Re-Irradiation with Particle Beams: A Case Report

Re-irradiation with X-rays and particle beams can be used to treat localized recurrence of unresectable head and neck cancer after initial irradiation therapy. However, re-irradiation therapy increases the risk of severe and late sequelae by 4-to 8-fold. It can also result in fatal outcomes, such as rupture of the carotid artery and cerebral necrosis or abscess. A 41-year-old woman was diagnosed with squamous cell carcinoma of the external auditory canal. The patient was initially treated with X-ray irradiation. However, the patient underwent re-irradiation with heavy particle beams and neutron rays for a recurrent tumor. The patient developed necrosis of the skull base involving the facial skin and temporal bone 2 months after the last session of re-irradiation therapy. The tissue in the parapharyngeal and masticatory regions also became completely necrotic, resulting in extensive exposure of the brain parenchyma. Although the patient underwent conservative and surgical treatment, necrosis of the tissue progressed, and a large part of the brain was exposed. Approximately 2.5 years later, although the brain is still exposed, the patient is alive without disease. Although the tumor had subsided and long-term survival was achieved, our patient developed serious osteoradionecrosis of the skull base with extensive brain exposure. For patients who are not candidates for surgery, re-irradiation alone is an option, albeit with poor prospects. This approach should be discussed with the patient while balancing the potential survival gain against the burden of treatment and the risk of complications.