Meningiomas, which arise from tissues that cover the brain and spinal cord, represent about a fifth of all brain tumors, and they affect women more often than men . The reason for a female predominance is not known, although most meningiomas express receptors for progesterone and some also express estrogen or androgen receptors . Most arise from the arachnoid villi in association with the dura mater or intracranial venous sinuses. Meningiomas are typically slow growing and may compress the brain, but they usually do not invade neural tissues or metastasize to distant sites. Many meningiomas are asymptomatic, discovered only as incidental findings at autopsy or on brain imaging studies performed for some other reason (e.g. ordered because of headache or light-headedness) .
In a nationwide case-control study, Danish investigators recently reported associations between menopausal hormone therapy (HT) and meningioma . Their findings, which are largely consistent with other observational research, are also notable from the perspectives of interpretation, perception, and validity.
The authors searched the Danish Cancer Registry for new cases of intracranial meningioma occurring between 2000 and 2009. They identified 924 cases among women aged 55–84 years without prior cancer diagnoses. These women were compared to similar women without meningioma. HT use was ascertained in a prescription registry established in 1995. The primary finding is that women who filled at least two prescriptions for HT during the time under consideration faced a 30% increased risk of meningioma compared to women who filled no prescriptions or just one prescription (odds ratio (OR) 1.3, 95% confidence interval (CI) 1.1–1.5). After at least 10 years of cumulative hormone use, risk was increased by 70% (95% CI 1.2–2.3). A heightened risk was observed among current as well as past users and among estrogen-only as well as estrogen–progestogen users .
Victor W. Henderson
Departments of Health Research & Policy and of Neurology & Neurological Sciences, Stanford University, Stanford, California, United States