Brain Tumors: Primary - Risk Factors

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Ethnicity

The risk for primary brain tumors in Caucasians is higher -- as much as twofold depending on type -- than in African-Americans.

Environmental or Occupational Risk Factors

Radiation Exposure. People who receive radiation therapy to the head during cancer treatment have an increased risk of developing brain tumors 10 - 15 years later. Workers in the nuclear industry are also at increased risk.

There is no evidence that electromagnetic field exposure from power lines or household appliances poses any risk. Several recent epidemiological studies, including a 2006 study in the British Medical Journal, found that cell phones, cordless phones, and wireless devices are also safe and do not increase the risk for gliomas.

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Chemical and Metals in Brain Tumors. High exposure to numerous metals and chemicals have been associated with brain tumors:

• Industrial chemicals, including vinyl chloride and petroleum products
• Lead, arsenic, or mercury exposure
• Exposure to pesticides. A major study of pesticides is underway, but results are not in yet. A 2003 study indicated that parental exposure to pesticides or herbicides did not appear to be important in increasing risk for brain cancer in their children.

Brain cancer is uncommon, and, over the course of their lifetime, many people are exposed to these chemicals, many of which are very common. To date, there has been no clear evidence that implicates any specific industrial chemical or metal.

Inherited Disorders

About 5% of primary brain tumors are associated with hereditary disorders. They include:

• Li-Fraumeni cancer family syndrome
• Tuberous sclerosis
• Von Recklinghausen disease (neurofibromatosis)
• Von Hippel Lindau disease
• Familial polyposis (Turcot's syndrome)
• Osler-Weber-Rendu syndrome

Organ Transplantation

A 2002 study reported a higher risk for brain cancers in patients who had undergone organ transplantations. Researchers believed that the drugs used to suppress the immune response after the procedures may increase the risk.

Medical Conditions Associated with a Lower Risk for Brain Tumors

A 2002 study reported lower risks for brain cancers in individuals with allergies and autoimmune diseases (such as type 1 diabetes). Autoimmune diseases were also associated with a lower risk for meningiomas. The cause of this possible association remains unknown.

Studies have also found an association between lower risk for gliomas and a history of infection with varicella zoster, the virus that causes chicken pox and shingles.

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Review Date: 10/19/2006
Reviewed By: Harvey Simon, M.D., Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

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