Objective: To discuss a rare but devastating complication following radiotherapy to the head and neck: radiation-induced malignancies of the temporal bone.
Study design: A retrospective case review comprising five patients with radiation-induced tumors involving the temporal bone.
Setting: A tertiary referral center.
Patients: Patients with tumors involving the temporal bone who have satisfied the criteria for being considered radiation-associated.
Main outcome measures: Initial tumor histology, radiation-induced tumor histology, latency between radiotherapy and diagnosis of the radiation-associated malignancy, amount of radiation received, therapeutic interventions, and survival statistics for each patient.
Results: Five cases of radiation-induced tumors of the temporal bone are presented (two osteosarcomas, two fibrosarcomas, and one squamous cell carcinoma). All five temporal bone tumors occurred in individuals that had previously received > 5,000 cGy of radiation. The initial histologic diagnoses included two astrocytomas, a glomus jugulare, a malignant meningioma, and a vestibular schwannoma. There was an average latency period of 15 years (range, 7-23 years) between completion of radiation and diagnosis of the malignancy. Four patients were treated with resection plus chemotherapy, and one decided against therapy. The prognosis was poor, with survival time of 7-14 months after the diagnosis of the radiation-induced tumor. Only one patient survived > 14 months and is currently free of disease, 3 years after diagnosis of the radiation-induced tumor.
Conclusions: Although radiation-induced tumors of the temporal bone occur with a very low incidence, their prognosis is extremely poor. The remote possibility of a radiation-associated tumor should be factored in when deciding upon the most appropriate therapeutic modality for individuals with neoplasms of the CNS and head and neck. Such considerations are particularly germane when contemplating radiation therapy for a benign lesion (e.g., glomus jugulare, acoustic neuroma, or meningioma) in an individual with a long predicted lifespan.