Radiation-induced meningiomas
Radiation-induced meningiomas are more frequently multiple and have a very long latency period. Meningiomas are a much more frequent complication of radiation exposure compared to sarcomas or gliomas.
Epidemiology
The exact incidence of radiation-induced meningiomas is unknown; one study had an incidence of 22% . There is an increasing incidence of developing meningiomas over time, unlike radiation-induced gliomas that have a stable/decreased incidence 5 years post-treatment . Radiation-induced meningiomas tend to occur in younger patients when compared to spontaneous meningiomas .
Pathology
There is a long latency between radiation exposure and diagnosis of radiation-induced meningiomas, on average ~35 years. They are more likely to be multiple, more aggressive, and have higher rates of recurrence than spontaneous meningiomas .
Etiology
Increased incidence of meningiomas has been documented in populations with radiation exposure that has come from therapeutic, diagnostic and environmental exposures :
- whole brain radiotherapy for childhood leukemia
- radiotherapy for tinea capitis
- whole mouth dental radiographs (increased risk in examinations performed pre-1945 when doses were higher)
- survivors of the Hiroshima and Nagasaki atomic bombings