The Type of Brain Cancer
Brain cancer consists of many types. When drawn from the originator, we can distinguish between primary brain cancer (ie, starting in the brain), with secondary brain cancer (starting with other organs in the body such as the lung or breast and then spreading to the brain). In adults, metastatic cancer to the brain is actually more common than primary brain cancer. This cancer is not treated in the same way. For example, breast or lung cancer that spreads to the brain is treated differently than the cancer that begins in the brain. The discussion here is only about primary brain cancer.
Unlike other types of cancer, brain cancer or spinal cord cancer rarely spreads to distant organs. They cause damage because they spread locally and destroy the normal brain tissue in the place where they appear. However, brain or spinal cord cancer is rarely considered "benign". Unless they have actually been removed or destroyed, most brain cancers or spinal cord tumors will continue to develop and eventually result in death.
Primary brain cancer can begin in one type of tissue or cells in the brain or spinal cord. Some tumors contain a mixture of cell types. Tumors in different regions of the central nervous system can be treated differently and have different prognoses.
A. Glioma:
Gliomas are a common term for a group of brain tumors that begin in glial cells. A number of tumors may be considered gliomas, including glioblastoma, astrocytomas, oligodendrogliomas, and ependymomas. About 4 out of 10 cases of brain cancer are gliomas. When calculated cases of malignant brain cancer, about 8 out of 10 is glioma.
A1. Astrocytomas:
Most of the tumors that arise in the brain itself begin in a glial cell called astrocytes. This tumor is called astrocytomas. Statisti k is about 3 out of 10 brain cancers.
Most astrocytomas can spread throughout the brain and blend into normal brain tissue, which can make them very difficult to remove surgically. Sometimes they spread along the path of the main nervous system. It is rare for them to spread outside the brain or spinal cord.
Astrocytomas are often classified as low, middle, or high grade, based on how cells look under a microscope.
- Low grade astrocytomas: the slowest growing type
- Anaplastic astrocytomas: grow at moderate levels
- Highest grade astrocytoma (or glioblastoma): fastest growing. These tumors make up about two-thirds of astrocytomas and are the most common type of brain cancer (malignant) that affects adults.
A2. Oligodendrogliomas: This brain tumor starts in brain cells called oligodendrocytes. Like astrocytomas, most can infiltrate nearby brain tissue and can not be completely removed by surgery. Oligodendrogliomas are sometimes scattered along central nervous system pathways but rarely spread outside the brain or spinal cord. A very aggressive type of tumor is known as anaplastic oligodendrogliomas. Only about 3% of oligodendrogliomas type of brain tumors.
A3. Ependymomas: These brain tumors are derived from ependymal cells, which are the ventricular lines. Ependymomas can block the central nervous system outflow from the ventricle, which causes a condition called hydrocephalus.
Unlike astrocytomas and oligodendrogliomas, ependymomas usually do not grow into the normal brain tissue. As a result, some (but not all) ependymomas can be completely removed and cured by surgery. Ependymomas spinal cord has the greatest chance of being cured by surgery. Ependymomas can spread along CSF pathways but do not spread beyond the brain or spinal cord. The most aggressive form is known as anaplastic ependymomas and usually can not be cured by surgery. Only about 2% of brain tumors are ependymomas.
B. Meningioma
Meningiomas are the most common brain tumors in adults . They arise from the meninges, the tissue lining that surrounds the outside of the brain and spinal cord. Meningioma contributes to about 1 in 3 primary brain cancers and spinal cord cancer.
The risk of this type of brain tumor increases with age. They are about twice as common in women. In some cases these tumors are genetic (inherited), especially in those with neurofibromatosis (benign tumor syndrome in neural tissue).
Meningiomas cause symptoms by suppressing the brain or spinal cord. About 4 of 5 meningiomas are benign, and most can be cured by surgery. But some meningiomas grow very close to the vital structures in the brain and can not be cured by surgery alone. A small number of meningiomas are malignant and may return many times after surgery or even spread to other parts of the body.
Also Read : 9 Early Symptoms of Brain Cancer In Children
C. Medulloblastomas
Medulloblastomas are brain tumors that develop from neuroectodermal cells (primitive nerve cells) in the cerebellum. They are cancer that grows fast and often spreads throughout the path of cerebrospinal fluid, but they can be treated with radiation therapy and chemotherapy. Medulloblastomas occur more frequently in children than in adults. They are part of a class of tumors called primitive neuroectodermal tumors (PNETs) that can occur in the cerebrum and elsewhere in the central nervous system.
D. Gangliogliomas
Brain tumors containing neurons and glial cells are called gangliogliomas. It is very rare in adults and has high recovery prospects with surgery alone or surgery combined with radiotherapy.
E. Schwannomas (neurilemomas)
Schwannomas are derived from Schwann cells, which form the myelin nerve fibers of the skull and other peripheral nerves.This type of brain tumor is usually benign. They can arise from cranial nerves. When they form tumors of the cranial nerves responsible for close balance of the cerebellum, they are called vestibular schwannomas or acoustic neuromas. They may also arise from the spinal cord after they have left the spinal cord. Schwannomas make up about 9% of all CNS tumors.
Other tumors that can start in or near the brain:
Chordomas: These tumors rarely start in the bones at the base of the skull or at the lower end of the spine. Chordomas are not from the central nervous system, but they can cause injury to the nearby nervous system by suppressing it. These tumors are treated with surgical removal whenever possible, and followed by radiotherapy, but they tend to return in the same area after treatment, which can lead to progressive injury and death. They usually do not spread to other organs.
Non-Hodgkin lymphoma: Lymphoma begins in lymphocytes (one of the major cell types of the immune system). Some types of central nervous system lymphoma (CNS) occur in people with immune system problems, such as those infected with HIV. The development of new treatments for AIDS, causing the type of brain lymphoma to be less common in recent years.Brain lymphoma is often very malignant and can be difficult to treat. Recent advances in chemotherapy, however, have improved the prognosis of these cancer patients.