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Brain cancer is a disease where malignant tumors are found in the brain. Whether it is in the brain or another part of the body, tumors are made of a mass of cells that multiply out of control. Tumors can be benign or malignant.
Benign brain tumors are abnormal collections of cells that multiply slowly and usually remain isolated from the surrounding normal brain tissue. These tumors grow slowly, do not spread to other parts of the brain, and are generally easier to remove than malignant tumors. Malignant tumors multiply and grow rapidly. It is difficult to differentiate these tumors from the surrounding normal brain tissue. Because of this, it is difficult to remove them completely without damaging the surrounding brain tissue.
Benign and malignant tumors can be classified into different groups depending on the type of cells from which they originate.
Benign tumors can be classified as follow:
- Chordomas, which arise from embryonic cells in the spinal cord or the base of the cranial nerve.
- Hemangioblastomas, which originate in the blood vessels.
- Meningiomas, which begin in the membrane covering the brain.
- Osteomas, in the bones of the skull
- Pinealoma, in the pineal gland.
- Pituitary adenomas, in the pituitary gland.
- Schwannomas, in the cells surrounding the nerves.
Some types of tumors, such as meningiomas (arise in the meninges, the lining of the brain) or germ cell tumors, can be benign in some cases and malignant in others.
This article is about malignant (cancerous) brain tumors.
Brain tumors are relatively rare but are often fatal. The most common malignant brain tumors are gliomas, in which cells called neuroglial cells (nerve supporting cells) become cancerous. Glioblastoma multiforme is the most common of all gliomas. Glioblastoma multiforme and anaplastic astrocytoma are fast-growing gliomas. Oligodendroglioma, another form of glioma, is rare and occurs primarily in adults. Gliomas account for 50% to 60% of all brain tumors (malignant and benign) in children and adults.
Medulloblastoma, which originates from the medulla cells at the base of the brain, is the most common type of brain tumor in children. It usually occurs before puberty.
Finally, sarcoma and adenocarcinoma are two extremely rare types of brain tumors.
Causes of brain cancer
The exact causes of cancer are still unknown. A brain tumor that starts in the brain itself is called a primary brain tumor. It can spread and destroy surrounding areas of the brain. Cancer of the breast, lung, skin, or blood cells (leukemia or lymphoma) can also spread (metastasize) to the brain, causing metastatic brain cancer. These clusters of cancer cells can then multiply in a single area or in different parts of the brain.
Known risk factors for brain cancer include:
- A history of radiation to the head.
- Immunosuppression (e.g., people taking medications that weaken the immune system, people with HIV, AIDS).
- Exposure to vinyl chloride a chemical used in the manufacture of plastics.
Symptoms and complications
A brain tumor causes symptoms when it puts pressure on the brain or destroys brain tissue. Symptoms depend on the size and location of the tumor, as well as how quickly it multiplies.
Although headaches are often a symptom of brain tumors, it is important to remember that most headaches are not caused by cancer, but by less serious conditions such as migraines or tension. Headaches caused by a brain tumor are often intense, accompanied by nausea and vomiting, and are often most severe early in the day. They may last for a long period of time or occur intermittently.
Other symptoms include:
- Coordination problems.
- Weakness or numbness on one side of the body.
- Vision problems, such as double vision.
- Confusion or difficulty concentrating.
- Changes in mood, senses, personality, or emotions.
- Memory problems.
The presence of any of the above symptoms may lead a doctor to suspect brain cancer. A CT scan or magnetic resonance imaging (MRI) is the first test that should be performed to properly diagnose any type of brain tumor. These specialized tests can detect many types of brain tumors and accurately determine their location and size. However, they do not determine whether or not the tumor is cancerous.
A biopsy must be performed to determine if the tumor is malignant. During the biopsy, a sample of the tumor is removed. If the tumor is too deep in the brain, surgeons may use a technique called stereotactic biopsy or three-dimensional needle placement.
This technique uses an MRI to create a three-dimensional image of the brain, which is then used to guide a needle into the appropriate area of the brain. Tumor cells are aspirated and collected in the needle for analysis. After collection, the biopsy sample is analyzed with microscopes and special chemicals to determine the type of tumor. It usually takes a few days to get the results of a biopsy.
Brain tumor cells can sometimes be obtained from cerebrospinal fluid (CSF), a special fluid that surrounds the brain and spinal cord. The CSF is collected with a thin needle inserted into the lower back under local anesthesia; this procedure is called a lumbar puncture (spinal tap).
This procedure cannot be performed if too much pressure builds up in the brain. This is because the change in intracranial pressure due to the puncture can cause some of the brain tissue at the base of the skull to be sucked out, which can lead to serious complications.
Treatment and prevention
Brain tumors are usually treated with a combined strategy of surgery, chemotherapy (anticancer drugs), and radiation, combined with medications to control symptoms.
During radiation, high doses of steroids are often given to reduce swelling caused by the tumor. This often relieves all or some of the symptoms but does not affect the tumor itself. Anticonvulsants may be used to prevent seizures.
Surgery is performed to remove as much of the cancerous tissue as possible. Some brain tumors are in areas that surgeons cannot reach without damaging other important parts of the brain. In these cases, it is often better not to operate. Even if surgery does not completely remove the tumor, it can reduce the size of the tumor and relieve some of the symptoms, and it can maximize the effectiveness of other treatments.
Surgery is usually followed by radiation and chemotherapy. In most cases, these procedures cannot fully destroy the tumor, but they can keep it under control for months.
If the brain tumor causes seizures, your doctor may prescribe anticonvulsant medicines.
Treatment for metastatic cancers depends largely on where the cancer originated. For example, lung cancer that has metastasized to the brain is treated the same way as other lung cancers. The part of the cancer that has invaded the brain may be treated with radiation. If the metastases are confined to one area of the brain, surgery is sometimes used to remove them.
Advances in technology offer new treatment options such as the use of lasers and ultrasound to remove tumors. “Gamma Knife” stereotactic radiosurgery is an alternative technique to surgery that directs beams of radiation directly and precisely at the tumor. These new techniques may be able to remove more tumor cells and minimize damage to healthy brain tissue around the tumor, reducing neurological complications.
It is usually not possible to remove all cancerous brain cells. If even a small number of cells remain, the cancer may return.
Our Doctor’s opinion
New treatment techniques such as radiosurgery, stereotactic surgery, and the administration of chemotherapeutic agents directly into the brain have greatly improved the prognosis of brain tumors and improved the quality of life and survival of people with this type of cancer. Most importantly limit your exposure to radiation and live a healthy lifestyle.