Meningiomas are common intracranial tumors affecting predominantly women and the elderly. Although their histology is typically benign, meningiomas can act in a malignant fashion because of their critical intracranial location. Presentation is due to focal neurologic dysfunction, seizures or headaches. Diagnosis before death is now readily accomplished with sophisticated neuro-imaging such as computed tomography and magnetic resonance imaging of the head. Treatment relies on surgical removal, but recurrences are common. The cost of this condition is great considering not only morbidity and mortality but also diagnosis and treatment. The cost may increase as more ubiquitous neuro-imaging leads to more people being diagnosed with this condition. Much could be gained by identifying etiologic risk factors for meningioma and preventing the disease. Few epidemiologic studies of intracranial meningioma have been done since the introduction of sophisticated neuro-imaging in the mid 1970s and its more widespread use in the l98Os. The present study will be both descriptive and analytic. In the descriptive study, all residents of King, Pierce and Snohomish counties in western Washington (estimated population 2.5 million) with a histologically confirmed intracranial meningioma will be identified using the Cancer Surveillance System (CSS) at the Fred Hutchinson Cancer Research Center in Seattle. Beginning in January, 1992, the CSS was enhanced to include the identification of all such patients in these counties. Neuropathologists will review tissue to confirm the diagnosis, and assays of sex hormone receptors will be performed on all specimens. Incidence rates will be calculated by age, gender and race. These patients will be recruited (estimated n=200) into a case-control study, the aim of which is to determine whether the risk of meningioma is increased by exposure to ionizing radiation (chiefly dental x-rays), to endogenous and exogenous estrogens and progestins, and to prior head trauma. Previous studies have suggested that these three classes of exposures may increase the risk of developing an intracranial meningioma. Two age- and gender-matched controls will be identified for each case using random-digit dialing if the case is under 65 years old or random selection from a list of Medicare beneficiaries in the three counties if the case is 65 years or older. All subjects will undergo an in-person standardized interview. Conditional logistic regression will be used to obtain adjusted odds ratios for the exposures controlling for potential confounders. We will also explore the relation between the exposures and the imaging results, histopathologic features, and sex hormone binding characteristics of the tumor. The long-term goal of this study is to reduce the incidence of meningioma by identifying its etiologic risk factors.
