Secondary malignancy following radiotherapy for thyroid eye disease.
OBJECTIVE
To describe the first case of a secondary meningioma in a patient after radiation treatment for thyroid eye disease (TED). Secondarily to identify any additional cases of secondary malignancy resulting from radiotherapy for thyroid eye disease from our institutional experience.


BACKGROUND
Thyroid eye disease (TED) is a self-limiting auto-immune disorder causing expansion of orbital soft tissue from deposition of glycosaminoglycans and collagen, leading to significant cosmetic and functional morbidity. Established management options for TED include: glucocorticosteroids, orbital radiotherapy, and surgical orbital decompression. Two large series on radiotherapy for TED have been reported without any cases of secondary malignancy.


METHODS
The case of a patient with visual failure, found to have a sphenoid wing meningioma after previous TED radiotherapy is described. We then reviewed 575 patients with at least 3-year follow-up receiving radiotherapy for TED at British Columbia Cancer Agency to identify other possible secondary malignancies.


RESULTS
The patient had postoperative improvement in her vision without any identified complications. Three additional cases of hematologic malignancy were identified. The calculated risk in our population of developing a radiation-induced meningioma after TED with at least 3 years of follow-up of is 0.17% (1/575); with hematopoetic malignancies the risk for secondary malignancy is 0.7% (4/575).


CONCLUSIONS
Our calculated risk for secondary malignancy (0.17%, 0.7%) is similar to the reported theoretical risk published in the literature (0.3-1.2%). There is real risk for the development of a secondary malignancy after radiotherapy treatment of TED and treatment options should include consideration for this potential.
Division of Neurosurgery, Department of Surgery, University of Nebraska Medical Center, Omaha, NE, United States; Division of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
Christopher C
CC
Gillis
Department of Otolaryngology, University of Nebraska Medical Center, Omaha, NE, United States; Division of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
Eun Hae
EH
Chang
Weil Cornell Medical College at Qatar, Al Rayyan, Qatar; Division of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
Khalid
K
Al-Kharazi
Division of Radiation Oncology and Developmental Radiotherapeutics, University of British Columbia, Vancouver, BC, Canada; Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC, Canada; Division of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
Tom
T
Pickles
Meningioma; Radiotherapy; Secondary malignancy; Thyroid eye disease