BRAIN CANCER

 

What is Brain Cancer?

The brain, like any other tissue in the body, is made up of individual cells which are much smaller than a pinpoint, and require a microscope to see them. These cells are the smallest units which compose the brain, and there are several different types. A brain cancer can arise from any of the cells which make up the brain. Basically, the brain's thinking cells (called "neurons") are meant to divide rapidly before birth, and up until about 7 years old. At this time the brain is fully grown, and contains all the "neurons "that it ever will. Further development is by the existing cells making increasingly elaborate connections with each other, to communicate with one another.
Once the brain cells stop dividing in childhood, they are never meant to divide again. If the brain is injured, such as by trauma or a stroke, specific cells within the brain (the "glial cells" ) divide to form scar tissue, but the brain's thinking cells (the neurons) don't reproduce (although damaged ones may be repaired). You can see that the division of brain cells is under strict regulation and control. When this control is lost in a single cell, then it starts dividing in an uncontrolled manner. Brain cancer starts in just one cell. As the cell makes more and more copies of itself, it grows to form a tumor (which means a swelling). A benign tumor stays where it starts, although it can grow very large and press on crucial areas. In contrast, a malignant tumor has a capacity to spread, and is then called "brain cancer". "Primary" brain cancer starts within the brain, and is the main subject of this transcript. In contrast, "secondary" brain cancer starts in some other organ (like lung or breast) and then spreads to the brain. This is called "brain metastasis".

 

What causes or increases the risk for Brain Cancer?

Like any cancer, the exact reason why one person gets brain cancer and another doesn't is unknown. However, several things have been found to increase the risk of developing brain cancer:

1) having rare family diseases, carried in the genes, such as Neurofibromatosis (the "Elephant Man" syndrome), Von-Hippel Lindau, Sturge-Weber's or Turcot's syndrome. These all belong to a family of diseases called the "phacomacoses" and present with cysts or bumps on or inside the body and high risk for brain tumors.

2) Exposure to certain chemicals, including chlorinated hydrocarbons (like PVC) and benzene, is associated with a higher risk of brain cancers.

3) Exposure to radiation has also been connected to developing brain cancers as well as other malignancies. The risk is greater if the person is exposed to at a young age to a higher dose. Pre-existing benign type tumors may become cancerous (called "malignant degeneration) if radiated.

What are the Symptoms of Brain Cancer?

This depends upon where in the brain the cancer arises, and how big it becomes before coming to medical attention. The brain has particular areas controlling thought, sight, hearing, sensation, movement, coordination and mood. The upper brain area tends to control the more advanced thought functions, while the middle controls mood and movement and the rear (or "brain stem") stimulates breathing and heart rate.

How common is brain cancer?

There are about 15,000 cases per year in the United States of "primary brain cancer". This causes about 10,000 deaths per year. Thus primary brain cancers account for 2% of the cancers yearly in the U.S.A. Much more common is brain Metastasis with at least 80,000 cases per year in the U.S.A. Since many cancers spread to the brain, and it is a critical structure, this accounts for almost 20% of total cancer deaths each year. While primary brain tumors account for 20% of the cancers in children, the majority of cases are in older individuals.

How are Brain Tumors Diagnosed and Evaluated?

A tumor simply means a swelling, and isn't necessarily cancer. A patient will come to the doctor with symptoms suspicious for a brain tumor, and the physician will perform a neurological examination to check the nerves or the brain which control the eyes and face, check for equal strength and sensation on both sides of the body, coordination and balance, and memory and judgment. He will look into the eyes for signs of increased pressure in the skull, such as swelling of the optic disks.
 

- The next step is to order a radiological test to look for the tumor. Most commonly a CAT scan is gotten which an array of X-ray beams to visualize the brain. Often contrast material is injected into a vein during the CAT scan, as this highlight abnormal area in the brain. This test takes about 1/2 hour and the films are read by a radiologist. Large tumors are very easily seen on CAT scan, but ones smaller than 1 cm or in the cerebellum may not be obvious.
If a tumor is seen, or there is still high suspicion of one, the next test ordered is a Magnetic Resonance Image (MRI) scan; it doesn't use radiation and is very accurate for detecting even small brain tumors in the cerebellum. It takes about an hour of lying still, is painless, and is much more expensive than a CAT scan, which is why they only order it after confirming a tumor.
 

- The only way to be absolutely sure of what kind of tumor is present is to take a sample (biopsy) of it. Nowadays, biopsies are very safe (less than 1% of patients die from them) and are usually obtained under stereo tactic guidance (a fine-needle is exactly placed into the tumor after visualizing it in 3 dimensions) The biopsy material is examined by a pathologist, a doctor who specializes in diagnosing disease from tissue samples. He does special stains on it and examines it under a microscope to see what type of tumor it is, and grades it depending upon how aggressive it looks. Rarely, the type of tumor is so obvious from the scans or is so deep in the brain that a biopsy isn't gotten; the tumor is treated based upon what it's presumed to be. Other possible tests include an MRI of the spine for certain tumors (medulloblastoma and high grade ependymoma) which tend to seed down the spine, a spinal tap to look for cancer cells shedding into the cerebral-spinal fluid that bathes the brain and spinal cord, and an endocrine (hormonal) blood test evaluation for pituitary or midbrain tumors. We may test to look for the origin of the tumor elsewhere in the body if it is believed not to have started in the brain. Spread of primary brain tumors to other body organs is very rare, but when it occurs it's usually to lung or bone marrow.
 

- Historically, treatment of brain tumors has used surgery, radiation treatment and/or chemotherapy. Each of these has improved dramatically over the past decades.

It is critical for the patient to get the correct treatment for brain cancer, the first time. This is because treatment of relapsed cancer isn't as successful as proper initial treatment when the diagnosis is first made. Nonetheless, newer techniques of pinpoint-accuracy radiation, microsurgery, chemotherapy and gene therapy offer more hope to the patient with brain cancer than ever before.
 

- Cancer Answers material explains, in plain English, the specifics of the particular therapies and the latest effective treatment - everything you need to know to deal knowledgably with a brain cancer problem.