What are Brain Tumors?
Brain tumors are abnormal growths made up of cells whose growth and division are no longer under the control of the body. They can occur in the cerebrum (the largest portion of the brain responsible for planning movement, interpreting sensation, and controlling memory, learning, "thinking", and emotions), the cerebellum (controls balance and equilibrium), or the brainstem (responsible for controlling heart rate, breathing, and consciousness). The causes for brain tumors are not known. Although brain tumors can occur at any age, they are most common in children between the ages 3-12 years, and adults ages 40-70 years. Malignant brain tumors represent a little less than 2% of all cancers in the U.S. (approx. 17,000 cases a year).

Brain tumors can either be benign or malignant.

• Benign tumors tend to grow slowly, do not invade surrounding normal tissues, and usually have well defined borders. They can often be successfuly treated with surgery. Benign tumors may still cause problems, however, because they compress and damage normal brain structures.

• Malignant tumors (cancer) invade and infiltrate normal, healthy tissues and often grow rapidly. They can arise within the brain itself (primary brain cancer), or they can begin in another organ of the body and spread to the brain (metastatic brain cancer). Malignant brain tumors are less likely to be cured with surgery alone. Treatment with radiation and/or chemotherapy is usually required for optimal results.

There are several types of primary brain cancers, each arising from a specific type of cell in the brain. Common primary brain cancers include astrocytomas (and their sub-types such as glioblastoma multiforme), oligodendogliomas, ependymomas, medulloblastomas, and CNS lymphomas. Brain cancers also vary in terms of their aggressiveness - i.e., how fast they grow and how readily they invade surrounding tissues. The most aggressive forms of brain cancer are called high grade, lesser degrees of aggressiveness are referred to as low grade. Tumor grade is determined by examining a sample of the tumor under the microscope.

How are Brain Tumors Treated?
The treatment of a brain tumor depends on several factors: (1) the type of tumor, (2) its grade (aggressiveness), (3) its size, and (4) its location in the brain. The age and general health of the patient also influences the choice of treatment. Ultimately, the patient and physician must balance the expected benefits of a treatment against possible risks and side effects when developing a treatment plan.

Common treatment methods include:

• Surgery - This is the most common form of therapy for brain tumors. It is also used to obtain a sample (biopsy) of the tumor for microscopic examination and confirmation of the diagnosis. To remove a brain tumor, a neurosurgeon makes an opening in the skull (craniotomy). If the tumor cannot be completely removed without damaging normal parts of the brain, the surgeon may only remove as much as possible to increase the effectiveness of subsequent radiation therapy or chemotherapy. Surgery is most successful for benign brain tumors and low grade malignant tumors.

• Radiation therapy - Used when all tumor cells cannot be removed completely by surgery, or when surgery is not technically possible. This form of treatment kills tumor cells using energy derived from radioisotopes implanted directly into the tumor, or from machines that generate x-ray or gamma radiation beams externally. Typically, the dose of radiation is divided into several smaller "fractions" which are then administered 5 days a week over a period of several weeks. This is done to reduce the risk of radiation injury to normal brain.

  Another form of radiation therapy, used in special circumstances, is radiosurgery. This technique is designed to focus high levels of energy on a tumor. Because the delivery of radiation to the tumor is precisiely guided by computers, very little radiation reaches normal brain tissue. Radiosurgery is administered as a single dose.

• Chemotherapy - The use of drugs to kill cancer cells. The theoretical advantage of chemotherapy is that it may reach cancer cells that cannot be detected at surgery, or are not visible of CT or MRI scan. Chemotherapy may be used as part of the initial therapy, or may be used when a tumor relapses after surgey or radiation therapy. Chemotherapy may also be given along with radiation, or following surgery, to enhance the effectiveness of these treatment modalities. Chemotherapy is most commonly administered intravenously and orally. Typically, treatments are repeated every 4-6 weeks for a period of time to achieve maximum beneficial effect.

Because safer and more effective forms of treatment for brain cancer are constantly being developed, physicians may offer patients the opportunity to participate in a clinical trial evaluating a promising new treatment method.

More Information on Brain Cancer on the World Wide Web:

A Primer of Brain Tumors - A Patient's Reference Manual (American Brain Tumor Association) - A well written document for patients with information on different types of brain tumors, diagnosis of brain tumors, and side effects of brain tumor treatment.

American Brain Tumor Association - Information for patients on brain tumors and their treatment. Guides for finding clinical trials.

Brain Tumor Society - An excellent source of patient information about brain tumors. Resources for families. Frequently asked questions about brain tumors.

National Brain Tumor Foundation - Information about brain tumors. Connect with other patients, caregivers, and support groups via the internet.

Information about cancer clinical trials from the National Cancer Institute

Musella Foundation For Brain Tumor Research & Information - Focus on brain tumor treatment.

American Cancer Society - A good general source of cancer information for patients.

Childrens Brain Tumor Foundation - Focus on brain and spinal cord tumors in children.