Am I at risk for a brain tumor?

In the United States in 2007, it is estimated that there were approximately20,000 new cases of primary brain tumors, and 14,000 deaths from primary brain tumors. About 85% of primary brain tumors arise from the glial cells of the brain. Unfortunately, many of these tumors (35-45%) are the most aggressive type (Glioblastoma Multiforme). The peak age at which people are diagnosed with brain tumors varies with the tumor type, however when taking all types into account the average age is about 50 years of age. Brain tumors generally comprise about 2% of all newly diagnosed adult cancers.
Exposure to radiation has been linked to the development of certain types of primary brain tumors, especially if the exposure took place in childhood. Higher radiation doses are generally felt to increase the risk of eventually developing a brain tumor, and radiation-induced brain tumors can take anywhere from 10-30 years to form.
Although many chemicals have been shown to cause brain tumors in laboratory animals, there have never been any definite associations with chemical exposures proven in human beings. Chemicals that have been shown to cause brain tumors in animals include n-nitroso compounds, vinyl chloride, and certain organic solvents. However, when examining populations exposed to these various chemicals (like pesticide workers or workers in the petrochemical industry), there has never been any conclusive evidence to suggest that they get brain tumors at a higher rate than people without the chemical exposures.
With the recent popularity of cellular phones, many people have worried that their use may be a risk factor for developing brain tumors. However, there has never been any data to support this idea. In fact, a few studies have looked at this question and there has been no conclusive evidence that cell phones increase the risk of brain tumors. There has also been concern regarding exposure to powerful magnetic fields (high power lines) and some sugar substitutes ( aspartame), however, there has not been any conclusive evidence linking these factors to increased risk of brain cancer.
Certain hereditary disorders can predispose someone to the development of certain brain tumors. Genetic diseases like neurofibromatosis type 1, neurofibromatosis type 2, von Hippel-Lindau disease, and tuberous sclerosis are all associated with an increased risk of developing a primary brain tumor.
Because there are so many different types of brain tumors, there are different risk factors for developing each of them. To learn about the risk factors for developing a specific a specific type of brain tumor, please refer to the OncoLink overview on that particular cancer.
How can I prevent brain tumors?
Currently, there are no proven strategies to prevent the development of primary brain tumors. Studies of diets rich in anti-oxidants have not shown any benefits in terms of lowering the risk of developing primary brain tumors.
It is possible to decrease the risk of developing brain metastases from certain tumors by decreasing the risk of developing the initial primary tumor in the first place. (See the OncoLink overviews about specific primary cancers for more information on preventing various malignancies.) Sometimes, when patients have certain cancers (ie: lung) that are well controlled, they will be offered preventive radiation therapy to the brain in order to decrease the likelihood of developing brain metastases in the future. This is called prophylactic cranial radiation. (Please see the section of this overview below for more information on radiation therapy.)