Understanding Brain Tumors

Brain tumors are masses of abnormal cells that grow in or around the brain. Tumors develop when these abnormal cells multiply for unknown reasons.

There are two kinds of brain tumors:

Benign brain tumors – grow slowly have distinct borders and they appear normal under a microscope.

Malignant brain tumors – are what is known or considered as brain cancer. They grow rapidly and typically invade healthy areas of the brain.

There are tumors however, that though benign, may be considered malignant if they are located in a part of the brain that is critical, or if their size is life threatening.

Brain tumors are classified in two categories:

Primary brain tumors are those that originate within the brain.

Secondary metastatic brain tumors – come from cells that have broken away from cancers in other parts of the body and traveled to the brain. Metastatic brain tumors are automatically considered malignant because they develop from cancerous cells and grow rapidly.

What are the causes of brain tumors?

Brain tumors are commonly caused by a change in genetic structure. These changes in genetic structure could be missing or mutated genes. These in turn, cause abnormal cells. Abnormal cells with malignant potential create a tumor when they multiply. These genetic changes may be inherited, caused by the environment, or both.

Only about 5% of primary brain tumors are considered to be caused by inherited genes alone. Still, there are types of brain tumors, such as glioblastoma multiforme, that are commonly associated with inherited genes.

Treatments for primary brain tumors, such as high-dose ionizing radiation may, however rarely, cause secondary brain tumors. This happens usually when a patient is given radiation treatments over time. When people are exposed to chemicals like petrochemicals, pesticides and formaldehyde, they seem to be at an increased risk of developing a malignant brain tumor than those who are not exposed.

In a number of lab experiments, it has been found that certain viruses cause brain tumors in animals. In humans however, it is yet to be determined whether this is true. Another common belief is that electromagnetic fields may be linked to brain tumors. However, research has found no evidence supporting this theory.

Though there are a number of genetic and environmental factors that cause brain tumors, in most cases, the cause of brain tumors is not known.

Grading tumors

Tumor grade refers to the level of malignancy. Tumors are graded based on their appearance under a microscope. A tumor’s grade is also determined by their mitotic index (growth rate), vascularity (blood supply), presence of a necrotic (dead cells) center, invasive potential (border distinctness) and similarity to normal cells.

A malignant tumor may contain several grades of cells, but the most malignant grade of cell found will determine the grade for the entire tumor even if most of the tumor is a lower grade.

Grade I tumors are the least malignant. Grade I tumors develop slowly and, under the microscope, appear almost normal. Surgery is often sufficient treatment for grade I tumors. However, grade I tumors may still be life-threatening if they cannot be removed through or accessed for surgery.

Grade II tumors grow a bit faster than grade I tumors. They appear slightly abnormal under the microscope and may invade surrounding normal tissue. Grade II tumors sometimes recur as grade III tumors or higher.

Grade III tumors are malignant. They contain abnormal cells that actively reproduce. Thus they grow rapidly, and invade surrounding normal tissue. Grade III tumors frequently recur, usually as grade IV tumors.

Grade IV tumors are the most malignant. They reproduce very rapidly and have a very abnormal microscopic appearance. They also have a necrotic center. Grade IV tumors even cause new blood vessels to form to help support their rapid growth.

How to treat brain tumor?

There are a number of treatments available to treat a malignant brain tumor. However the type of treatment that a patient should be given is dependent upon a number of factors including the size of the tumor, its growth rate and the symptoms experienced by the patient.

Most treatments make extensive use of technology including intraoperative MRI, the latest Gamma Knife, stereotactic radiosurgery technology, brain mapping, and computer-assisted brain surgery.


Depending on the location of the tumor, surgery can be used to remove a brain tumor. If a tumor is small and not located near a critical part of your brain, your surgeon can easily separate it from surrounding healthy tissue. However, if the tumor is located near a sensitive area of your brain, surgery can be very risky. In cases such as this, your surgeon may remove as much of the tumor as is safe. The removal of even a portion of the tumor may relieve some the signs and symptoms you experience.

Surgically removing a brain tumor is risky. There can be infections and bleeding. Also, operating near critical areas is very dangerous. For instance operating near nerves that connect your eyes to your brain may cause blindness.

Radiation therapy

Radiation therapy uses beams of high-energy particles to kill tumor cells. Radiation therapy often comes from a machine outside the body (external beam radiation). External beam radiation can focus on the part of the brain where the tumor is located. It can also be applied to the entire brain.

This procedure is sometimes used after surgery to kills cells that were left. It can also be used if you have a number of brain tumors that cannot be removed through surgery. Whole brain radiation is usually used in cases where the cancer has metastasized to the brain.

However in rare cases, radiation can be put inside the body close to the tumor (brachytherapy).


Unlike traditional surgery, radio surgery uses multiple beams of radiation to form a highly focused form of radiation treatment. These focused beams of radiation kill the tumor cells in a very small area. Each beam is not particularly strong, but the point where all the beams meet – at the brain of tumor – gets a very large dose of radiation.


Chemotherapy uses drugs to treat brain tumors. The drugs can either be taken orally or intravenously (injected into a vein) for them to travel throughout the body.

Chemotherapy can also be injected into the spinal column so the treatment affects only the central nervous system. Another way of administering chemotherapy is by placing one or more disk-shaped wafers during surgery, in the area where the tumor had been. These disk-shaped wafers release chemotherapy over the next several days.

Targeted drug therapy

Targeted drug therapy works by focusing on the specific abnormalities present in the cancer cells. With these abnormalities blocked, the targeted drug therapy can kill the cancer cells.

Rehabilitation after treatment

Because the brain controls all body functions, brain tumors/cancer and treatments can affect motor skills, speech, vision and thinking. Thus, it is necessary for patients to undergo rehabilitation as part of recovery.

  • Cognitive rehabilitation helps you cope with or regain lost cognitive abilities.
  • Physical therapy helps you regain lost motor skills or muscle strength.
  • Vocational therapy can help you get back to work after a brain tumor or other illness.
  • Specialists in speech difficulties can help you with speech proble
    ms caused by a brain tumor and treatment or other illness.
  • Tutoring is particularly helpful for children who have brain tumors.