Cancer of the Brain and Central Nervous System and the Environment

The American Cancer Society (ACS) reports that cancers of the brain or spinal cord account for about 1.3% of all cancers and 2.2% of all cancer-related deaths among adults and children. Recommendations for preventing brain or central nervous system tumors are undefined because their causes are unknown. Cancers of the brain occur in people of all ages but more frequently in two age groups:

• Children aged younger than 15 years
• Adults aged 65 years and older

Cancers of the spinal cord are less common than cancers of the brain. Cancers of the brain and other parts of the central nervous system are more common in white persons. Cancers of the meninges, part of the central nervous system, are more common in women.

Little is known about the causes of childhood and adult cancers of the brain and other parts of the central nervous system. Several studies of environmental risk factors have presented inconsistent and inconclusive results.

Exposure and Risk

About 5% of brain tumors are due to hereditary factors. Persons with rare genetic conditions such as Li-Fraumeni cancer family syndrome, tuberous sclerosis, von Recklinghausen's disease (neurofibromatosis type 1), neurofibromatosis type 2, von Hippel-Lindau disease, and familial polyposis are at greater risk for cancer of the brain and other parts of the central nervous system.

Research is being conducted to determine whether additional factors may be linked to cancer of the brain and other parts of the central nervous system, However much more research is necessary. Other factors that have been investigated as include:

• Electromagnetic fields (including cellular and cordless phone use)
• Occupational exposure to asbestos, arsenic, wood dust, benzene, mercury, lead, pesticides, and other chemicals
• Ingestion of n-nitroso compounds through food, drinking water, and smoking
• Use of hair dyes and sprays
• Dietary calcium intake
• Infections
• Allergies and other immune system factors
• Drinking alcohol
• Genetic polymorphisms
• Family history
• Head trauma
• Reproductive and hormonal factors

Risk factors are different for children and for adults. Cancerous brain and spinal cord tumors are the second most common cancers in children. Little is known about the causes of this group of diseases. Established risk factors include exposure to therapeutic doses of ionizing radiation, rare hereditary syndromes, and family history.

Prevention

Recommendations for preventing brain or nervous system tumors are undefined because their causes are unknown. Avoiding unnecessary radiation exposure can prevent many types of cancer.