The etiology of the majority of meningiomas is unknown. Radiation is the only definite causative factor, with an increased incidence of meningiomas in children radiated with as little as 10 gray for tinea capitis (Modan et al 1974; Mack and Wilson 1993). Moderate radiation doses between 10 and 20 gray, as well as large doses greater than 20 gray and most often greater than 40 gray, also produce an increased rate of meningiomas (Harrison et al 1991; Mack and Wilson 1993). In 10 patients, most treated with greater than 40 gray, the median time to meningioma development was 20 years after the radiation (Harrison et al 1991).
In a large population-based study in Britain, the incidence of subsequent development of CNS tumors was compared with doses of both radiation and chemotherapy in a cohort of 17,980 patients surviving at least 5 years after the diagnosis of childhood cancer (Taylor et al 2010). In this large study, it was found that the risk of developing meningiomas had a strong, linear, and independent relationship with the dose of radiation to meningeal tissues, as well as to the dose of intrathecal methotrexate received. Specifically, compared to controls, radiation doses of 0.01 to 9.99, 10.00 to 19.99, 20.00 to 29.99, 30.00 to 39.99, and greater than or equal to 40 Gy administered to the meninges was associated with a 2-fold, 8-fold, 52-fold, 568-fold, and 479-fold increased risk, respectively.
There is little prospective evidence that head trauma plays an etiologic role in the development of meningiomas. In a prospective study of nearly 3000 patients with head injury, no increased incidence was found (Annegers et al 1979).
There has been ongoing investigation in regards to a hypothesis that cell phone use increases one’s risk of meningioma formation. However, at this point in time, a review of the current data seems to argue against this hypothesis, at least in regards of up to 15 years of cell phone use (Swerdlow et al 2011). Longitudinal studies beyond 15 years are still needed to further define whether cell phone use is correlated with the incidence of meningiomas.
Although the presence of androgen receptors in meningiomas has long been established, the relationship between exogenous hormonal therapy and development of meningiomas has been under investigation. In a large prospective study of over one million postmenopausal women, there was a relative risk of 1.34 (95% CI 1.03 to 1.75) of meningioma in women being treated with hormonal replacement therapy as compared to non-users (Benson et al 2010), suggesting a slightly increased risk.