BRAIN TUMOR FACTS
Brain and spinal cord tumors are abnormal growths of tissue found inside the skull or the bony spinal column. The word tumor is used to describe both abnormal growths that are new (neoplasms) and those present at birth (congenital tumors).
No matter where they are located in the body, tumors are usually classed as benign (or non-cancerous) if the cells that make up the growth are similar to other normal cells, grow relatively slowly, and are confined to one location. Tumors are called malignant (or cancerous) when the cells are very different from normal cells, grow relatively quickly, and can spread easily to other locations.
In most parts of the body, benign tumors are not particularly harmful. This is not necessarily true in the brain and spinal cord, which are the primary components of the central nervous system (CNS). Because the CNS is housed within rigid, bony quarters (that is, the skull and spinal column), any abnormal growth can place pressure on sensitive tissues and impair function. Also, any tumor located near vital brain structures or sensitive spinal cord nerves can seriously threaten health. If a benign tumor is found deep inside the brain, surgery to remove it may be very risky because of the chances of damaging vital brain centers. On the other hand, a benign tumor located near the brain's surface can often be removed surgically.
An important difference between malignant tumors in the CNS and those elsewhere in the body lies with their potential to spread. While malignant cells elsewhere in the body can easily feed tumors inside the brain and spinal cord, malignant CNS tumors rarely spread out to other body parts. Laboratory and clinical investigators are exploring the basis of these unusual characteristics of CNS tumors, because these unique properties may suggest new strategies to prevent or treat them.
What causes brain tumors?
When newly formed tumors begin within the brain or spinal cord, they are called primary tumors. Primary CNS tumors rarely grow from neurons - nerve cells that perform the nervous system's important functions - because once neurons are mature they no longer divide and multiply. Instead, most tumors are caused by out-of-control growth among cells that surround and support neurons. Primary CNS tumors - such as gliomas and meningiomas - are named by the types of cells comprising them, their location, or both.
In a small number of individuals, primary tumors may result from specific genetic diseases - such as neurofibromatosis and tuberous sclerosis - or exposure to radiation or cancer-causing chemicals. Although smoking, alcohol consumption, and certain dietary habits are associated with some types of cancers, they have not been linked to primary brain and spinal cord tumors.
In fact, the cause of most primary brain and spinal cord tumors - and most cancers - remains a mystery. Scientists do not know exactly why and how cells in the nervous system or elsewhere in the body lose their normal identity as nerve, blood, skin, or other cell types and grow uncontrollably. Research scientists are looking for clues to this process with the goals of learning why and how cancer begins and developing new tools to stop it. Some of the possible causes under investigation include viruses, defective genes, and chemicals.
Metastatic tumors are caused by cancerous cells that shed from tumors in other parts of the body, travel through the bloodstream, burrow through the blood vessel walls, latch onto tissue, and spawn new tumors inside the brain or spinal cord.
For every four people who have cancer that has spread within the body, one develops metastasis within the CNS. The top two culprits that lead to these secondary CNS tumors are lung and breast cancer. Other, less frequent causes of CNS metastases include kidney (renal) cancer, lymphoma (a cancer affecting immune cells), prostate cancer, and melanoma, a form of skin cancer.
How many people have brain tumors?
Research studies suggest that new brain tumors arise in more than 40,000 Americans each year. About half of these tumors are primary, and the remainder are metastatic.
Individuals of any age can develop a brain tumor. In fact, they are the second most common cause of cancer-related death in people up to the age of 35, with a slight peak in occurrence among children between the ages of 6 and 9. However, brain tumors are most common among middle-aged and older adults. People in their 60s face the highest risk - each year 1 of every 5,000 people in this age group develops a brain tumor.
No matter where they are located in the body, tumors are usually classed as benign (or non-cancerous) if the cells that make up the growth are similar to other normal cells, grow relatively slowly, and are confined to one location. Tumors are called malignant (or cancerous) when the cells are very different from normal cells, grow relatively quickly, and can spread easily to other locations.
In most parts of the body, benign tumors are not particularly harmful. This is not necessarily true in the brain and spinal cord, which are the primary components of the central nervous system (CNS). Because the CNS is housed within rigid, bony quarters (that is, the skull and spinal column), any abnormal growth can place pressure on sensitive tissues and impair function. Also, any tumor located near vital brain structures or sensitive spinal cord nerves can seriously threaten health. If a benign tumor is found deep inside the brain, surgery to remove it may be very risky because of the chances of damaging vital brain centers. On the other hand, a benign tumor located near the brain's surface can often be removed surgically.
An important difference between malignant tumors in the CNS and those elsewhere in the body lies with their potential to spread. While malignant cells elsewhere in the body can easily feed tumors inside the brain and spinal cord, malignant CNS tumors rarely spread out to other body parts. Laboratory and clinical investigators are exploring the basis of these unusual characteristics of CNS tumors, because these unique properties may suggest new strategies to prevent or treat them.
What causes brain tumors?
When newly formed tumors begin within the brain or spinal cord, they are called primary tumors. Primary CNS tumors rarely grow from neurons - nerve cells that perform the nervous system's important functions - because once neurons are mature they no longer divide and multiply. Instead, most tumors are caused by out-of-control growth among cells that surround and support neurons. Primary CNS tumors - such as gliomas and meningiomas - are named by the types of cells comprising them, their location, or both.
In a small number of individuals, primary tumors may result from specific genetic diseases - such as neurofibromatosis and tuberous sclerosis - or exposure to radiation or cancer-causing chemicals. Although smoking, alcohol consumption, and certain dietary habits are associated with some types of cancers, they have not been linked to primary brain and spinal cord tumors.
In fact, the cause of most primary brain and spinal cord tumors - and most cancers - remains a mystery. Scientists do not know exactly why and how cells in the nervous system or elsewhere in the body lose their normal identity as nerve, blood, skin, or other cell types and grow uncontrollably. Research scientists are looking for clues to this process with the goals of learning why and how cancer begins and developing new tools to stop it. Some of the possible causes under investigation include viruses, defective genes, and chemicals.
Metastatic tumors are caused by cancerous cells that shed from tumors in other parts of the body, travel through the bloodstream, burrow through the blood vessel walls, latch onto tissue, and spawn new tumors inside the brain or spinal cord.
For every four people who have cancer that has spread within the body, one develops metastasis within the CNS. The top two culprits that lead to these secondary CNS tumors are lung and breast cancer. Other, less frequent causes of CNS metastases include kidney (renal) cancer, lymphoma (a cancer affecting immune cells), prostate cancer, and melanoma, a form of skin cancer.
How many people have brain tumors?
Research studies suggest that new brain tumors arise in more than 40,000 Americans each year. About half of these tumors are primary, and the remainder are metastatic.
Individuals of any age can develop a brain tumor. In fact, they are the second most common cause of cancer-related death in people up to the age of 35, with a slight peak in occurrence among children between the ages of 6 and 9. However, brain tumors are most common among middle-aged and older adults. People in their 60s face the highest risk - each year 1 of every 5,000 people in this age group develops a brain tumor.
