An adult brain tumour is a disease in which abnormal cells form in the tissues of the brain.
There are many types of brain and spinal cord tumours. The tumours are formed by the abnormal growth of cells and may begin in different parts of the brain or spinal cord. Together, the brain and spinal cord make up the central nervous system (CNS).
The tumours may be either benign (not cancer) or malignant (cancer):
Benign brain and spinal cord tumours grow and press on nearby areas of the brain. They rarely spread into other tissues and may recur (come back).
Malignant brain and spinal cord tumours are likely to grow quickly and spread into other brain tissue.
When a tumour grows into or presses on an area of the brain, it may stop that part of the brain from working the way it should. Both benign and malignant brain tumours cause symptoms and need treatment.
Brain and spinal cord tumours can occur in both adults and children. However, treatment for children may be different than treatment for adults.
A brain tumour that starts in another part of the body and spreads to the brain is called a metastatic tumour.
tumours that start in the brain are called primary brain tumours. Primary brain tumours may spread to other parts of the brain or to the spine. They rarely spread to other parts of the body.
Often, tumours found in the brain have started somewhere else in the body and spread to one or more parts of the brain. These are called metastatic brain tumours (or brain metastases). Metastatic brain tumours are more common than primary brain tumours.
About half of metastatic brain tumours are from lung cancer. Other types of cancer that commonly spread to the brain are melanoma and cancer of the breast, colon, kidney, nasopharynx, and unknown primary site. Leukemia, lymphoma, breast cancer, and gastrointestinal cancer may spread to the leptomeninges (the two innermost membranes covering the brain and spinal cord).
The brain controls many important body functions.
The brain has three major parts:
The cerebrum is the largest part of the brain. It is at the top of the head. The cerebrum controls thinking, learning, problem solving, emotions, speech, reading, writing, and voluntary movement.
The cerebellum is in the lower back of the brain (near the middle of the back of the head). It controls movement, balance, and posture.
The brain stem connects the brain to the spinal cord. It is in the lowest part of the brain (just above the back of the neck). The brain stem controls breathing, heart rate, and the nerves and muscles used to see, hear, walk, talk, and eat.
(1) Anatomy of the brain, showing the cerebrum, cerebellum, brain stem, and other parts of the brain. (2) Anatomy of the inside of the brain, showing the pineal and pituitary glands, optic nerve, ventricles (with cerebrospinal fluid shown in blue), and other parts of the brain.
The spinal cord connects the brain to nerves in most parts of the body.
The spinal cord is a column of nerve tissue that runs from the brain stem down the center of the back. It is covered by three thin layers of tissue called membranes. These membranes are surrounded by the vertebrae (back bones). Spinal cord nerves carry messages between the brain and the rest of the body, such as a signal from the brain that makes muscles move or a signal from the skin to the brain that it senses heat.
There are different types of brain and spinal cord tumours.
Brain and spinal cord tumours are named based on the type of cell they formed in and where the tumour first formed in the CNS. The grade of a tumour may be used to tell the difference between slow-growing and fast-growing types of the tumour. The grade of a tumour is based on how abnormal the cancer cells look under a microscope and how quickly the tumour is likely to grow and spread.
Tumour Grading System
- Grade I (low-grade): The tumour grows slowly, has cells that look a lot like normal cells, and rarely spreads into nearby tissues. Grade I brain tumours may be cured if they are completely removed by surgery.
- Grade II: The tumour grows slowly, but may spread into nearby tissue and may recur (come back). Some tumours may become a higher-grade tumour.
- Grade III: The tumour grows quickly, is likely to spread into nearby tissue, and the tumour cells look very different from normal cells.
- Grade IV (high-grade): The tumour grows and spreads very quickly and the cells do not look like normal cells. There may be areas of dead cells in the tumour. Grade IV tumours usually cannot be cured.
The following types of tumours can form in the brain or spinal cord:
An astrocytic tumour begins in star-shaped brain cells called astrocytes, which help keep nerve cells healthy. An astrocyte is a type of glial cell. Glial cells sometimes form tumours called gliomas. Astrocytic tumours include the following:
- Brain stem glioma (usually high grade): A brain stem glioma forms in the brain stem, which is the part of the brain connected to the spinal cord. It is often a high-grade tumour, which spreads widely through the brain stem and is hard to cure. Brain stem gliomas are rare in adults. (Click here for more information on Childhood Brain Stem Glioma.)
- Pineal astrocytic tumour (any grade): A pineal astrocytic tumour forms in tissue around the pineal gland and may be any grade. The pineal gland is a tiny organ in the brain that makes melatonin, a hormone that helps control the sleeping and waking cycle.
- Pilocytic astrocytoma (grade I): A pilocytic astrocytoma grows slowly in the brain or spinal cord. It may be in the form of a cyst and rarely spreads into nearby tissues. Pilocytic astrocytomas can often be cured.
- Diffuse astrocytoma (grade II): A diffuse astrocytoma grows slowly, but often spreads into nearby tissues. The tumour cells look something like normal cells. In some cases, a diffuse astrocytoma can be cured. It is also called a low-grade diffuse astrocytoma.
- Anaplastic astrocytoma (grade III): An anaplastic astrocytoma grows quickly and spreads into nearby tissues. The tumour cells look different from normal cells. This type of tumour usually cannot be cured. An anaplastic astrocytoma is also called a malignant astrocytoma or high-grade astrocytoma.
- Glioblastoma (grade IV): A glioblastoma grows and spreads very quickly. The tumour cells look very different from normal cells. This type of tumour usually cannot be cured. It is also called glioblastoma multiforme.
- Gliosarcoma: Gliosarcoma is a very rare primary mixed tumor in the central nervous system. Its onset is between the fourth and sixth decade of life, and it has a male/female ratio of 1.8/1. Gliosarcoma's represent about 2% of glioblastoma diagnoses. Standard treatment consists in surgical resection of the tumor followed in some cases by external radiotherapy and chemotherapy.
An oligodendroglial tumour begins in brain cells called oligodendrocytes, which help keep nerve cells healthy. An oligodendrocyte is a type of glial cell. Oligodendrocytes sometimes form tumours called oligodendrogliomas. Grades of oligodendroglial tumours include the following:
- Oligodendroglioma (grade II): An oligodendroglioma grows slowly, but often spreads into nearby tissues. The tumour cells look something like normal cells. In some cases, an oligodendroglioma can be cured.
- Anaplastic oligodendroglioma (grade III): An anaplastic oligodendroglioma grows quickly and spreads into nearby tissues. The tumour cells look different from normal cells. This type of tumour usually cannot be cured.
A ganglioglioma is a rare type of brain tumor, accounting for approximately 1% of all brain tumors. Gangliogliomas occur when a single cell in the brain starts to divide into more cells, forming a tumor. This can occur when the cell randomly acquires changes (mutations) in genes that regulate how a cell divides. Most gangliogliomas grow slowly and are considered benign. However, up to 10% of gangliogliomas may grow more rapidly and become malignant, meaning the tumor affects the surrounding brain tissue. The main treatment for ganglioglioma is removal of the entire tumor during surgery. If the entire tumor is not removed, it has the potential to recur and may require additional surgery or treatments, such as radiation therapy or chemotherapy. Unfortunately, because gangliogliomas are quite rare, there is limited information to show that radiation therapy or chemotherapy are effective treatments for this condition.
A mixed glioma is a brain tumour that has two types of tumour cells in it — oligodendrocytes and astrocytes. This type of mixed tumour is called an oligoastrocytoma.
- Oligoastrocytoma (grade II): An oligoastrocytoma is a slow-growing tumour. The tumour cells look something like normal cells. In some cases, an oligoastrocytoma can be cured.
- Anaplastic oligoastrocytoma (grade III): An anaplastic oligoastrocytoma grows quickly and spreads into nearby tissues. The tumour cells look different from normal cells. This type of tumour has a worse prognosis than oligoastrocytoma (grade II).
An ependymal tumour usually begins in cells that line the fluid -filled spaces in the brain and around the spinal cord. An ependymal tumour may also be called an ependymoma. Grades of ependymomas include the following:
- Ependymoma (grade I or II): A grade I or II ependymoma grows slowly and has cells that look something like normal cells. There are two types of grade I ependymoma — myxopapillary ependymoma and subependymoma. A grade II ependymoma grows in a ventricle (fluid-filled space in the brain) and its connecting paths or in the spinal cord. In some cases, a grade I or II ependymoma can be cured.
- Anaplastic ependymoma (grade III): An anaplastic ependymoma grows quickly and spreads into nearby tissues. The tumour cells look different from normal cells. This type of tumour usually has a worse prognosis than a grade I or II ependymoma.
A medulloblastoma is a type of embryonal tumour. Medulloblastomas are most common in children or young adults.
Pineal Parenchymal tumours
A pineal parenchymal tumour forms in parenchymal cells or pineocytes, which are the cells that make up most of the pineal gland. These tumours are different from pineal astrocytic tumours. Grades of pineal parenchymal tumours include the following:
- Pineocytoma (grade II): A pineocytoma is a slow-growing pineal tumour.
- Pineoblastoma (grade IV): A pineoblastoma is a rare tumour that is very likely to spread.
A meningeal tumour, also called a meningioma, forms in the meninges (thin layers of tissue that cover the brain and spinal cord). It can form from different types of brain or spinal cord cells. Meningiomas are most common in adults. Types of meningeal tumours include the following:
- Meningioma (grade I): A grade I meningioma is the most common type of meningeal tumour. A grade I meningioma is a slow-growing tumour. It forms most often in the dura mater (the layer of tissue that covers the brain and is closest to the skull). A grade I meningioma can be cured if it is completely removed by surgery.
- Meningioma (grade II and III): This is a rare meningeal tumour. It grows quickly and is likely to spread within the brain and spinal cord. The prognosis is worse than a grade I meningioma because the tumour usually cannot be completely removed by surgery.
- Hemangiopericytoma: A hemangiopericytoma is not a meningeal tumour but is treated like a grade II or III meningioma. A hemangiopericytoma usually forms in the dura mater. The prognosis is worse than a grade I meningioma because the tumour usually cannot be completely removed by surgery.
Germ Cell tumours
A germ cell tumour forms in germ cells, which are the cells that develop into sperm in men or ova (eggs) in women. There are different types of germ cell tumours. These include:
- Embryonal yolk sac carcinomas
Germ cell tumours can be either benign or malignant.
Craniopharyngioma (Grade I)
A craniopharyngioma is a rare tumour that usually forms just above the pituitary gland (a pea-sized organ at the bottom of the brain that controls other glands). Craniopharyngiomas can form from different types of brain or spinal cord cells. They begin in the center of the brain, just above the back of the nose.
Recurrent Brain tumours
A recurrent brain tumour is a tumour that has recurred (come back) after it has been treated. Brain tumours often recur, sometimes many years after the first tumour. The tumour may recur at the same place in the brain or in other parts of the central nervous system.
Having certain genetic syndromes may affect the risk of developing a brain tumour.
Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your doctor if you think you may be at risk. There are few known risk factors for brain tumours. The following conditions may increase the risk of certain types of brain tumours:
Being exposed to vinyl chloride may increase the risk of glioma.
Infection with the Epstein-Barr virus, having AIDS (acquired immunodeficiency syndrome), or receiving an organ transplant may increase the risk of primary CNS lymphoma.
Having certain genetic syndromes may increase the risk brain tumours:
Neurofibromatosis type 1 (NF1) or 2 (NF2).
von Hippel-Lindau disease.
Turcot syndrome type 1 or 2.
Nevoid basal cell carcinoma syndrome.
The cause of most adult brain and spinal cord tumours is unknown.
The symptoms of adult brain and spinal cord tumours are not the same in every person.
The symptoms caused by a primary brain tumour depend on where the tumour begins in the brain, what that part of the brain controls, and the size of the tumour. Headaches and other symptoms may be caused by brain tumours. Other conditions, including cancer that has spread to the brain, may cause the same symptoms. Check with your doctor if you have any of the following problems:
Morning headache or headache that goes away after vomiting.
Frequent nausea and vomiting.
Loss of appetite.
Vision, hearing, and speech problems.
Loss of balance and trouble walking.
Unusual sleepiness or change in activity level.
Changes in personality, mood, ability to focus, or behavior.
Spinal Cord tumours
Back pain or pain that spreads from the back towards the arms or legs.
A change in bowel habits or trouble urinating.
Weakness in the legs.
Tests that examine the brain and spinal cord are used to diagnose adult brain and spinal cord tumours.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Neurological exam: A series of questions and tests to check the brain, spinal cord, and nerve function. The exam checks a person’s mental status, coordination, and ability to walk normally, and how well the muscles, senses, and reflexes work. This may also be called a neuro exam or a neurologic exam.
- Visual field exam: An exam to check a person’s field of vision (the total area in which objects can be seen). This test measures both central vision (how much a person can see when looking straight ahead) and peripheral vision (how much a person can see in all other directions while staring straight ahead). Any loss of vision may be a sign of a tumour that has damaged or pressed on the parts of the brain that affect eyesight.
- tumour marker test: A procedure in which a sample of blood, urine, or tissue is checked to measure the amounts of certain substances made by organs, tissues, or tumour cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the body. These are called tumour markers. This test may be done to diagnose a germ cell tumour.
- Gene testing: A laboratory test in which a sample of blood or tissue is tested for changes in a chromosome that has been linked with a certain type of brain tumour. This test may be done to diagnose an inherited syndrome.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- MRI (magnetic resonance imaging) with gadolinium: A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of the brain and spinal cord. A substance called gadolinium is injected into a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI). Sometimes a procedure called magnetic resonance spectroscopy (MRS) is done during the MRI scan. An MRS is used to diagnose tumours, based on their chemical make-up. MRI is often used to diagnose tumours in the spinal cord.
- SPECT scan (single photon emission computed tomography scan): A procedure that uses a special camera linked to a computer to make a 3-dimensional (3-D) picture of the brain. A small amount of a radioactive substance is injected into a vein or inhaled through the nose. As the substance travels through the blood, the camera rotates around the head and takes pictures of the brain. Blood flow and metabolism are higher than normal in areas where cancer cells are growing. These areas will show up brighter in the picture. This procedure may be done just before or after a CT scan. SPECT is used to tell the difference between a primary tumour and a tumour that has spread to the brain from somewhere else in the body.
- PET scan (positron emission tomography scan): A procedure to find malignant tumour cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the brain. Malignant tumour cells show up brighter in the picture because they are more active and take up more glucose than normal cells do. PET is used to tell the difference between a primary tumour and a tumour that has spread to the brain from somewhere else in the body.
- Angiogram: A procedure to look at blood vessels and the flow of blood in the brain. A contrast dye is injected into the blood vessel. As the contrast dye moves through the blood vessel, x-rays are taken to see if the vessel is blocked.
A biopsy is also used to diagnose a brain tumour.
If imaging tests show there may be a brain tumour, a biopsy is usually done. One of the following types of biopsies may be used:
- Stereotactic biopsy: When imaging tests show there may be a tumour deep in the brain in a hard to reach place, a stereotactic brain biopsy may be done. This kind of biopsy uses a computer and a 3-dimensional scanning device to find the tumour and guide the needle used to remove the tissue. A small incision is made in the scalp and a small hole is drilled through the skull. A biopsy needle is inserted through the hole to remove cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer.
- Open biopsy: When imaging tests show that there may be a tumour that can be removed by surgery, an open biopsy may be done. A part of the skull is removed in an operation called a craniotomy. A sample of brain tissue is removed and viewed under a microscope by a pathologist. If cancer cells are found, some or all of the tumour may be removed during the same surgery. Tests are done before surgery to find the areas around the tumour that are important for normal brain function. There are also ways to test brain function during surgery. The doctor will use the results of these tests to remove as much of the tumour as possible with the least damage to normal tissue in the brain.
Craniotomy: An opening is made in the skull and a piece of the skull is removed to show part of the brain.
The pathologist checks the biopsy sample to find out the type and grade of brain tumour. The grade of the tumour is based on how the tumour cells look under a microscope and how quickly the tumour is likely to grow and spread.
The following tests may be done on the tumour tissue that is removed:
- Immunohistochemistry study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens. This type of study is used to tell the difference between different types of cancers.
- Light and electron microscopy: A laboratory test in which cells in a sample of tissue are viewed under regular and high-powered microscopes to look for certain changes in the cells.
- Cytogenetic analysis: A laboratory test in which cells in a sample of tissue are viewed under a microscope to look for certain changes in the chromosomes.
Sometimes a biopsy or surgery cannot be done.
For some tumours, a biopsy or surgery cannot be done safely because of where the tumour formed in the brain or spinal cord. These tumours are diagnosed and treated based on the results of imaging tests and other procedures.
Sometimes the results of imaging tests and other procedures show that the tumour is very likely to be benign and a biopsy is not done.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options for primary brain and spinal cord tumours depend on the following:
The type and grade of the tumour.
Where the tumour is in the brain or spinal cord.
Whether the tumour can be removed by surgery.
Whether cancer cells remain after surgery.
Whether there are certain changes in the chromosomes.
Whether the cancer has just been diagnosed or has recurred (come back).
- The patient's general health.
The prognosis and treatment options for metastatic brain and spinal cord tumours depend on the following:
Whether there are more than two tumours in the brain or spinal cord.
Where the tumour is in the brain or spinal cord.
How well the tumour responds to treatment.
Whether the primary tumour continues to grow or spread.
For more information on Brain Cancer click here
This link is to the National Cancer Institute (NCI) cancer website in the United States. There may be references to drugs and clinical trials that are not available here in Australia.
For information courtesy of cancer Australia, please click here