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Answers To Common Questions About Brain Tumors

When you have cancer, you likely have a lot to consider. That can be particularly true when you’re diagnosed with a brain tumor.

Following are some of the questions that may cross your mind. Neurosurgeon Ania Pollack, MD, provides answers.

What is a brain tumor?

A brain tumor is an abnormal growth of tissue in the brain or central nervous system that can disrupt proper brain function. There are two main categories of brain tumors. Primary brain tumors start in the brain or a structure of the brain. They may grow into other parts of the brain or into the spine, but rarely to other organs. Metastatic, or secondary, tumors begin in another part of the body, such as the breast or lung, and then spread to the brain. Metastatic tumors are much more common than primary brain tumors and are named by the location where they originate. For example, when lung cancer spreads to the brain, physicians consider it lung cancer in the brain — not brain cancer.

What is the difference between a benign tumor and a malignant tumor?

Primary brain tumors are categorized as either benign or malignant. Less aggressive brain tumors are called benign. They grow slowly and typically have clear borders that do not invade surrounding tissue. Meningiomas are an example of brain tumors that are usually benign.

Benign tumors can disrupt proper brain function by growing to a size where they are pressing on surrounding tissues.

Malignant brain tumors grow more rapidly, have uneven borders, and invade surrounding tissue. The majority of primary malignant brain tumors are a type of tumor known as a glioma.

Secondary, or metastatic, brain tumors start in another part of the body and spread to the brain, usually through the bloodstream. All metastatic brain tumors are considered malignant.

How many different types of brain tumors are there?

Classification of brain tumors is complex. There are more than 120 types of brain and nervous system tumors that develop from different cell types. They can form in different areas including brain tissue, cranial nerves (12 pairs of nerves that connect your brain to parts of your head, neck, and trunk), meninges (tissue that covers the brain), peripheral nerves (nerves outside the brain and spinal cord that connect the central nervous system to the rest of the body, such as limbs and organs), and more.

What are the risk factors for getting primary brain tumors?

Research is ongoing to find the answer to this question. Risk factors may include:

• Exposure to large doses of radiation over time, such as exposure to low electromagnetic fields, or certain chemicals
• Family history and genetic conditions

What can I do to avoid brain tumors?

Lifestyle, environment, and genes can all affect the likelihood of getting cancer. Living a healthy lifestyle by exercising, eating well, and avoiding tobacco use can lower your risk of cancer. Some brain tumors, however, occur spontaneously. So, stay aware of your health and wellness. If something doesn’t seem right, talk to your doctor.

What are the symptoms of a brain tumor?

Symptoms depend on where the tumor is located and how quickly it’s growing. For example, a tumor may affect fine motor skills (like the ability to hold a pencil), sensory skills, or speech if it’s compressing the parts of the brain that control those functions.

What is the difference between grades and stages of brain tumors?

In the brain, tumors are graded, not staged, as in other types of cancers. A stage tells you where a tumor is in relationship to the organ of origin, but stages don’t apply to brain tumors because they stay within the central nervous system.

There are three to four grades of gliomas, malignant tumors. Grade I glioma is usually a disease of childhood and can typically be cured by surgical removal. Grades II to IV are called brain cancer. Lower grades can progress to a more aggressive grade, so they are all considered to be malignant.

How does the genetic makeup of a tumor affect treatment?

Genetic makeup can predict how a tumor may respond to treatment. Genetic testing is available to help guide your treatment. Also to help determine a tumor’s response to treatment, your health care provider will check for specific tumor markers, or biomarkers. Biomarkers are substances made by tumors or by healthy cells in response to the tumors. When a tumor is present, tests will detect these markers at higher-than-normal levels. Tumor marker tests can help determine the treatment or combination of treatments that will work best for certain types of cancer.

What’s the role of surgery in treating a brain tumor?

If the tumor can be resected, or removed, without affecting brain function, surgery is usually the first line of treatment. For example, Grade I meningiomas don’t typically invade the brain, so they are much more likely to be resected successfully. On the other hand, high grade gliomas mix with, or infiltrate, normal brain cells, so these tumors are less likely to be resectable. If a tumor is located deep in the brain and surrounds critical structures like blood vessels it is more challenging to remove and requires a team that includes specialists in multiple neuroscience disciplines.

How do neurosurgeons ensure accuracy when removing a brain tumor?

Thanks to advances in technology and understanding of the brain, previously inoperable brain tumors can now be removed surgically. Before surgery, neurosurgeons can map the brain using technology such as functional MRIs to identify speech or motor areas in the brain. This enables surgeons to plan the surgery so they can improve the surgical outcome and reduce the risk of harming brain function.

In some cases, brain surgery can be performed while the patient is awake to help the surgical team avoid damaging healthy tissue and remove as much of the tumor as possible. This is relatively painless for the patient, as the brain lacks pain receptors. During surgery the neurosurgeon asks the patient to answer questions and perform simple tasks to make sure motor and speech function remain intact.

If a brain tumor can’t be removed by surgery, how is it treated?

A multidisciplinary approach is provided for primary brain tumors that require more than just surgery. First, surgery is done, if possible, then chemotherapy and/or radiation therapy may be used, based on tissue diagnosis. Although the tumor may shrink as a result of therapy, the main goal of treatment is to stop tumor growth and protect the patient’s condition from worsening.

For many years, it was thought that brain tumors would not respond favorably to chemotherapy due to the blood-brain barrier that protects the brain. Since then a chemotherapeutic agent has been developed to cross the blood-brain barrier. It has been widely used to treat primary brain cancers. External beam radiation can also be used.

What is stereotactic radiosurgery?

Stereotactic radiosurgery is a type of radiation therapy in which the radiation field is shaped to match the exact size and shape of the tumor. With precise planning, the tumor is located so that only the tumor is radiated – and not the tissue around it. Stereotactic radiosurgery is called surgery because the radiation is so precise, not because it involves cutting.

What’s on the horizon for the treatment of brain tumors?

A great deal of research is ongoing. One exciting area of study is cancer vaccines that encourage the immune system to attack cancer cells. Another is the use of viruses to damage cancer cells. Premier Health offers cancer patients numerous opportunities to participate in clinical trials of new treatments, therapies, and drugs.

Source: Ania Pollack, MD, Clinical Neuroscience Institute; American Association of Neurological Surgeons