Disease Facts

What is a brain tumor?

A brain tumor is an abnormal growth caused by cells that reproduce themselves uncontrollably. A brain tumor can be either benign or malignant. Benign tumors are not “cancerous” but can be dangerous depending on the location of the tumor in the brain.

Malignant brain tumors may remain in one area of the brain or may spread to other areas. Brain tumors are known as “primary brain tumors” if the growth starts in the brain, as opposed to starting in another area of the body and spreading to the brain, known as “secondary” or “metastic” tumors. Primary brain tumors rarely spread to the body outside of the central nervous system.

What are the symptoms of a brain tumor?

There are many symptoms of a brain tumor and you should consult your doctor immediately if you suspect that you or a loved one may be affected by one. Here are a few symptoms indicative of a brain tumor:

· Headache
· Loss of muscle control on one side of the body, however slight
· Inability to make facial expressions on one side of the face
· Seizures
· Change in ability to reason or cognitive functioning
· Diminished memory
· Fatigue
· Loss of spatial perception

Symptoms can be caused by the tumor or by swelling in the brain that is the body’s reaction to the tumor (called edema). Often, drugs can be prescribed to diminish the swelling and relieve some or even all of the symptoms.

How do you name a tumor?

Brain tumors are classified by the type of cell infected and the rate at which the tumor grows or spreads. A tumor may grow from a central mass and invade other areas of the brain or cells may spread to other areas of the brain and multiply that way. For example, a tumor that remains an isolated mass and spreads from that mass is similar to a tree that grows and spreads its roots and branches throughout the ground. On the other hand, a tumor that sheds cells to spread in other areas of the brain is similar to taking a handful of sand and throwing it into the grass so that there is not one identifiable mass.

The rate at which a tumor grows is categorized on a scale of one through four. A grade one tumor is the slowest growing, while a grade four is the fastest. Grades can change to become faster or slower depending on several factors, including the aggressiveness of the tumor and the effectiveness of treatments.

The second part of the name depends on the type of cell infected. For example, a “glioma” refers to cells in the supporting tissue of the brain. The most common are astrocytoma and oligodendroglioma.

How are tumors diagnosed?

The most accurate way to diagnose a brain tumor is by obtaining a biopsy. The biopsy will identify the type of cell infected and rate of infiltration or malignancy. It is important for the surgeon to obtain a comprehensive sample for a reliable diagnosis and information relating to treatment options. It is possible to have a tumor with more than one type of infected cell. It is also advisable to get a second opinion as to what the sample from the biopsy suggests as a diagnosis. A patient can and should have the samples, or “slides,” containing the biopsied cells sent to another facility to be examined.

Another common way to evaluate brain tumors is by MRI or non-intrusive scans. These methods provide an image of the abnormal cells based on heat the cells generate and the scan’s ability to photograph this phenomenon. This method can suggest the rate of malignancy and type of tumor but a biopsy must be used for exact diagnosis. Scans may also illustrate swelling or edema as opposed to tumor.

Why is the biopsy so important?

The initial biopsy will determine the initial diagnosis and subsequent treatment. The biopsy requires obtaining a sample from the patient’s brain and such an invasive procedure requires that the patient be strong enough and in good enough health to undergo such a procedure. For this reason it is not common practice to obtain multiple biopsies of the tumor during treatment.


Certain treatments, especially chemotherapies, will only be prescribed if the patient’s biopsy indicates a certain type of tumor. Newly released or experimental treatments often require a biopsy prior to the treatment being available to that patient. This presents a problem when a scan suggests that the tumor has mutated in grade or even cell type from the original diagnosis but the patient cannot undergo a new biopsy to confirm this suspicion.

An estimated 17,000 Americans are diagnosed with gliomas each year.

These tumors are extremely aggressive and deadly; only eight percent of patients survive two years, and three percent survive five years after diagnosis.