Cancers of the brain are the consequence of abnormal growths of cells in the brain. Brain cancers can arise from primary brain cells, from the cells that form other brain components (for example, membranes, blood vessels), or from the growth of cancer cells from other organs that have spread to the brain by the bloodstream (metastatic brain cancer).
Although many growths in the brain are popularly called brain tumors, not all brain tumors are cancerous. Cancer is a term reserved for malignant tumors.
Malignant tumors grow and spread aggressively, overpowering healthy cells by taking their space, blood, and nutrients. (Like all cells of the body, tumor cells need blood and nutrients to survive.) This is especially a problem in the brain, as the added growth within the closed confines of the skull can lead to an increase in intracranial pressure or the distortion of surrounding vital structures, causing their malfunction.
Tumors that do not grow aggressively are called benign. Almost all tumors that begin in the brain do not spread to other parts of the body. The major differences between benign and malignant tumors is that malignant tumors can invade the brain tissues and grow rapidly.
In general, a benign tumor is less serious than a malignant tumor. However, a benign tumor can still cause many problems in the brain.
Primary brain tumors
The brain is made up of many different types of cells.
Cancers occur when one type of cell transforms and loses its normal characteristics. Once transformed, the cells grow and multiply in abnormal ways.
As these abnormal cells grow, they become a mass of cells, or tumor.
Brain tumors that result from this transformation and abnormal growth of brain cells are called primary brain tumors because they originate in the brain.
The most common primary brain tumors are gliomas, meningiomas, pituitary adenomas, vestibular schwannomas, primary CNS lymphomas, and primitive neuroectodermal tumors (medulloblastomas). The term glioma is an expansive one since it includes numerous subtypes, including astrocytomas, oligodendrogliomas, ependymomas, and choroid plexus papillomas.
These primary tumors are named after the part of the brain or the type of brain cell from which they arise.
Brain tumors vary in their growth rate and ability to cause symptoms.
Metastatic brain tumors
Metastatic brain tumors are made of cancerous cells that spread through the bloodstream from a tumor located elsewhere in the body. The most common cancers that spread to the brain are those arising from the lung, breast, and kidney as well as malignant melanoma. The cells spread to the brain from another tumor in a process called metastasis. The process metastasis occurs when cancer cells leave the primary cancer tissue and enter either the lymphatic system to reach the blood or the bloodstream directly. These cancer cells eventually reach the brain tissue through the bloodstream where they develop into tumors.
Metastatic brain tumors are the most common type of tumor found in the brain and are much more common than primary brain tumors. Metastatic tumors are usually named after the type of tissue from which the original cancer cells arose (for example, metastatic lung or breast cancer). Brain blood flow usually determines where the metastatic cancer cells will lodge in the brain; about 85% locate in the cerebrum (the largest portion of the brain, located in the upper part of the skull cavity). Unfortunately, the majority of metastatic brain tumors occur at more than one site in the brain tissue.
In the United States, brain tumors are estimated to develop in about 22,000 people in 2009.
Brain Cancer Causes
As with tumors elsewhere in the body, the exact cause of most brain tumors is unknown.
The following factors have been proposed as possible risk factors for primary brain tumors, but whether these factors actually increase an individual's risk of a brain tumor is not known for sure.
Radiation to the head
An inherited (genetic) risk
Environmental toxins (for example, chemicals used in oil refineries, embalming chemicals, rubber industry chemicals)
Not all brain tumors cause symptoms, and some (such as tumors of the pituitary gland that cause no symptoms) are found mainly after death. The symptoms of brain tumors are numerous and not specific to brain tumors, meaning they can be caused by many other illnesses as well. The only way to know for sure what is causing the symptoms is to undergo diagnostic testing.
The symptoms are caused by the tumor pressing on or encroaching on other parts of the brain and keeping them from functioning normally.
Some symptoms are caused by swelling in the brain caused by the tumor or surrounding inflammation.
The symptoms of primary and metastatic brain cancers are similar.
The following symptoms are most common:
Other nonspecific symptoms and signs include the following:
Altered mental status: changes in concentration, memory, attention, or alertness
Nausea, vomiting: especially early in the morning
Abnormalities in vision
Difficulty with speech
Gradual changes in intellectual or emotional capacity
In many people, the onset of these symptoms is very gradual and may be overlooked by both the person with the brain tumor and the person's family members, even for long time periods. Occasionally, however, these symptoms appear more rapidly. In some instances, the person acts as if he or she is having a stroke.
When to Seek Medical Care
Unexplained, persistent vomiting
Double vision or unexplained blurring of vision, especially on only one side
Lethargy or increased sleepiness
New pattern or type of headaches, especially early morning headaches
Although headaches are thought to be a common symptom of brain cancer, they may not occur until late in the progression of the disease. If any significant change in a person's headache pattern occurs rapidly, health-care providers may suggest that you go the emergency department. If a person has a known brain tumor, any new symptoms or relatively sudden or rapid worsening of symptoms also warrants a trip to the nearest hospital emergency department. Be on the lookout for the following new symptoms:
Changes in mental status, such as excessive sleepiness, memory problems, or inability to concentrate
Visual changes or other sensory problems
Difficulty with speech or in expressing yourself
Changes in behavior or personality
Clumsiness or difficulty walking
Nausea or vomiting (especially in middle-aged or older people)
Brain tumors now cause more deaths among children than any other forms of cancer, many from cellphone use. Research did not support the cell phone industry's claims of safety. Because we don't yet know the health risks, we must exercise caution. Read on..
What causes and who is at risk for brain tumors?
No one knows the exact causes of brain tumors. Doctors can seldom explain why one person develops a brain tumor and another does not.
Research has shown that people with certain risk factors are more likely than others to develop a brain tumor. A risk factor is anything that increases a person's chance of developing a disease.
The following risk factors are associated with an increased chance of developing a primary brain tumor:
Being male - In general, brain tumors are more common in males than females. However, meningiomas are more common in females.
Race - Brain tumors occur more often among white people than among people of other races.
Age - Most brain tumors are detected in people who are 70 years old or older. However, brain tumors are the second most common cancer in children. (Leukemia is the most common childhood cancer.) Brain tumors are more common in children younger than 8 years old than in older children.
Family history - People with family members who have gliomas may be more likely to develop this disease.
Being exposed to radiation or certain chemicals at work:
Radiation - Workers in the nuclear industry have an increased risk of developing a brain tumor.
Formaldehyde - Pathologists and embalmers who work with formaldehyde have an increased risk of developing brain cancer. Scientists have not found an increased risk of brain cancer among other types of workers exposed to formaldehyde.
Vinyl chloride - Workers who make plastics may be exposed to vinyl chloride. This chemical may increase the risk of brain tumors.
Acrylonitrile - People who make textiles and plastics may be exposed to acrylonitrile. This exposure may increase the risk of brain cancer.
Scientists are investigating whether cell phones may cause brain tumors. Studies thus far have not found an increased risk of brain tumors among people who use cell phones.
Scientists also continue to study whether head injuries are a risk factor for brain tumors. So far, these studies have not found an increased risk among people who have had head injuries.
Most people who have known risk factors do not get brain cancer. On the other hand, many who do get the disease have none of these risk factors. People who think they may be at risk should discuss this concern with their doctor. The doctor may be able to suggest ways to reduce the risk and can plan an appropriate schedule for checkups.
This article has a lot more attached links and videos that point to the harm and hazard of cell phones, shown by research:
for the attached links to Brain Cancer.
In the United States, the annual incidence of brain cancer generally is 15–20 cases per 100,000 people. Brain cancer is the leading cause of cancer-related death in patients younger than age 35.
Primary brain tumors account for 50% of intracranial tumors and secondary brain cancer accounts for the remaining cases. Approximately 17,000 people in the United States are diagnosed with primary cancer each year and nearly 13,000 die of the disease. The annual incidence of primary brain cancer in children is about 3 per 100,000.
Secondary brain cancer occurs in 20–30% of patients with metastatic disease and incidence increases with age. In the United States, about 100,000 cases of secondary brain cancer are diagnosed each year.