Brain Cancer

Risk Factors

The American Cancer Society defines a risk factor as anything that increases a person's chance of getting a disease such as cancer. According to ACS, different cancers have different risk factors. For example, unprotected exposure to strong sunlight is a risk factor for skin cancer, and smoking is a risk factor for lung cancer. According to the American Cancer Society, the large majority of brain cancers are not associated with any risk factors. Most brain cancers simply happen for no apparent reason. A few risk factors associated with brain cancer are known.

Environmental Risk Factors
The only established environmental risk factor for brain tumors is radiation. Before the risks of radiation were recognized, children with ringworm of the scalp (a fungal infection) often received low-dose radiation therapy, which substantially increased the risk of brain tumors in later life. Today, most radiation-induced brain tumors are caused by radiation to the head given for the treatment of other cancers.

Other environmental factors such as exposure to vinyl chloride (an odorless gas used in the manufacturing of plastics), exposure to aspartame (a sugar substitute,) and exposure to electromagnetic fields from cellular telephones or high-tension wires have been suggested as risk factors, but most researchers in this field agree that no conclusive evidence exists that clearly implicates such exposure.

Immune System Disorders
People with impaired immune systems have an increased risk of developing lymphomas of the brain or spinal cord. Deficiencies of the immune system may be congenital (present at birth), may be a side effect of treatment for other cancers or to prevent rejection of transplanted organs, or the result of the acquired immunodeficiency syndrome (AIDS). Lymphomas are cancers of lymphocytes, a type of cell of the immune system. Lymphomas usually form in lymph nodes. Primary lymphoma of the central nervous system is less common than lymphoma that arises outside the brain but is increasing in frequency even among individuals without established impairment of the immune system. The cause for this increase is not known.

Family History
Rare cases of brain and spinal cord cancers run in families. In general, patients with familial cancer syndromes have multiple tumors that occur when they are young. Some of these families have well-known disorders. Neurofibromatosis type 2 is an inherited condition associated with schwannomas of both acoustic (hearing) nerves and in some patients, multiple meningiomas, or spinal cord ependymomas. Patients with tuberous sclerosis (another inherited condition) may have noninfiltrating subependymal giant cell astrocytomas in addition to benign tumors of the skin, heart, or kidneys. Von Hippel-Lindau disease is associated with an inherited tendency to develop hemangioblastomas (blood vessel tumors) of the cerebellum or retina as well as renal cell (kidney) carcinomas. Malignant brain tumors are rare in these disorders. Other families may have a genetic disorder that is not well recognized or that may even be unique to a particular family.

Brain cancer staging:
How Are Brain and Spinal Cord Tumors Staged?

Staging is the process of gathering information from certain examinations and diagnostic tests to determine how widespread a cancer is. The stage of a cancer is one of the most important factors in selecting treatment options. It is also helpful in determining the patient's prognosis (the outlook for chances of survival). A staging system is a standardized way in which the cancer care team describes the extent to which the cancer may have spread.

Malignant (cancerous) tumors of the brain and spinal cord (the central nervous system or CNS) differ in several important ways from tumors in other parts of the body. In the rest of the body, the most deadly aspect of a malignant tumor is its ability to spread. In contrast, tumors starting in the brain or spinal cord can spread to other parts of the CNS, but they almost never spread to other organs. The dangerous aspect of these tumors is that they can interfere with functions of the brain that are essential for life.

Benign (noncancerous) tumors do not spread from the organ they start in to other organs and do not even spread much within the organ where they originate. Because many parts of the brain are essential for life, any tumor (benign or malignant) starting in these areas may be impossible to remove by surgery and can become life-threatening.

At this time, the American Joint Committee on Cancer (AJCC) does not have a staging system for tumors in the brain or spinal cord. Prognostic factors have been identified. The most important prognostic factors are the cell type (such as astrocytoma, ependymoma, etc.) and grade (aggressiveness of the tumor cells). Other factors include the age of the patient, the extent of tumor remaining after an attempted surgical removal, the location of the tumor, the functional level of the patient (related to side effects caused by the tumor), spread of cancer cells through the cerebrospinal fluid to other parts of the brain and/or spinal cord and, very rarely, spread of cancer beyond the nervous system.

Systems have been proposed for staging of some childhood brain tumors. But, these systems have not been adopted by the AJCC or other oncology professional groups.

The Brain Tumor Society
Includes basic information about brain about brain tumors, patient/family resources frequently asked questions, health care providers, and survivor stories.

The Childhood Brain Tumor Foundation
Provides information about children's brain tumors, treatments, care centers, and new discoveries pertaining directly to children's care.

Skull Base Institute
Designed to show patients the type of surgeries that are available, including videos you can watch online.

Living with Cancer
Living with cancer, links to other helpful sites for learning more about treatments, diets, dealing with pain, noticing changes, and tools to help cancer patients with their recovery.

Stories and Faces
Includes stories about cancer patients and how they dealt with their disease. Also, there are links to the different kinds of treatments available along with information about the different types of brain cancer.

Brain Tumour Foundation of Canada
A Canadian Website providing an opportunity for people with brain tumors and their families share experiences, address personal issues, and gain support in a safe environment.

We Can Pediatric Brain Tumor Network
A helpful site for parents dealing with children who have brain cancer and events that will stimulate their diagnosed child to achieve more. Information on workshops for the parents and siblings of brain cancer patients to help them understand what their family member is going through.