Brain Cancer Risk Factors

Understanding Primary Brain Cancer

The abnormal growth of cells forming on the brain is not necessarily indicative of a brain cancer diagnosis. For example, over 90 percent of meningiomas (the second most common type of intrcranial tumor), are benign (non-cancerous) tumors. Brain tumors are either benign or malignant (cancerous). Benign brain tumors will not spread to other parts of the body but may still cause some health problems that require treatment.

Primary cancers are typically named for the localized area of origin. Primary brain cancer originates in the brain. Only a small percentage of malignant tumors originate in the brain. Cancer that has spread from elsewhere in the body is considered secondary brain cancer.

There are many different types of brain tumors, characterized by the cell or tissue that they affect. For example, a type of brain cancer called meningiomas arise within the meninges, which is the membrane surrounding the brain and the central nervous system.

Understanding Risk Factors for Brain Cancer

The risk for developing primary brain cancer is very low. The American Cancer Society estimates the risk over a lifetime is less than one percent. And, there is no single cause or risk factor directly linked to developing brain cancer.

Doctors have found exposure to certain chemicals, particularly those found in some industrial settings, may increase a person's likelihood of developing cancer. However, there is no conclusive evidence. You can not use risk factors to predict whether or not you will get a disease; a risk factor only affects the chances of developing a disease.

Risk Factors for Brain Cancer

• Gender:  There is not a general rule that covers all brain cancers. Certain cancers, like meningiomas, are twice as likely to develop in women. Medulloblastomas are more frequently found in males.
• Radiation Treatment:  Exposure to radiation therapy, particularly at a young age, may increase the likelihood of developing brain cancer.
• Chemical Exposure:  Exposure to certain industrial chemicals or solvents have been linked to an increased risk in developing brain cancer. Although it is not conclusive, there is evidence that there is a higher incidence of certain types of brain tumors in those working in oil refining, rubber manufacturing, and drug manufacturing.
• Genetic Links:  Family history may affect the likelihood of developing certain diseases, including brain cancer. Von Hippel-Lindau disease, Li-Fraumeni syndrome, and Neurofibromatosis (NF1 and NF2) are inherited conditions that have been found in families with a history of rare brain cancers. Otherwise, there is little evidence that brain cancer runs in families or that the development of brain tumors is linked to genetic factors.

NOTE: Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer. Not having risk factors does not mean that you won't get cancer. If you think you may be at risk, you should discuss it with your doctor.

Does Age Matter?

In general, the frequency of brain cancer increases with age, seeing more occurrences in people age 65 and older. However, when looking at specific types of brain tumors, the age factor will vary depending on the cell type or location of the tumor.

Adults have very low risk of developing medulloblastomas, a cancer occurring primarily in children. On the other hand, gliomas (tumors originating in the glial cells) are most common in adults. The incidence of meningiomas and craniopharyngiomas are also far more frequent in adults over age 50, but again, these tumors may occur at any age.

Assessing the Risk Factors of Brain Cancer

Primary brain cancer is very rare. It is important to remember a risk factor only affects the probability of developing brain cancer over a lifetime. For example, if you have received radiation therapy to treat another cancer, you may want to discuss what this means for your individual risk of developing brain cancer with your doctor. Or, if you have worked in a particular industry where you handled potentially cancerous chemicals, you and your doctor can work together to manage the potential risk from exposure.

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