Brain Cancer Overview
Brain and spinal cord (also known as central nervous system, or CNS) tumors are masses of abnormal cells in the brain or spinal cord that have grown out of control. These tumors can either be benign (non-cancerous) or malignant (cancerous).
Unlike cancers that start in other parts of the body, tumors which start in the brain or spinal cord rarely spread to distant organs. They can, however, travel short distances within the brain, causing damage to healthy tissue. Therefore, even benign tumors often need to be removed or destroyed.
Visit the National Cancer Institute where this information and more can be found about Brain Tumors and Brain Cancer, or ask your cancer care team questions about your individual situation.
Signs and Symptoms of Brain Tumors
Signs and symptoms of brain cancer can be either general or specific and depend on:
- Where the tumor forms in the brain or spinal cord
- The size of the tumor
- What the affected part of the brain controls
General symptoms of brain cancer are caused when the tumor is putting pressure on the brain or spinal cord. Specific symptoms are caused when the tumor is inhibiting the function of a specific part of the brain.
General symptoms of brain cancer may include:
- Difficulty falling or staying asleep
- Extreme drowsiness and fatigue
- Headaches that are severe or worsen with activity or during early morning hours
- Significant changes to memory or personality
- Sudden inability to walk or perform daily activities
- Nausea or vomiting
Certain symptoms, such as drowsiness, nausea, or fatigue could be related to conditions other than brain cancer. However, if you notice them in combination together or with any of the other symptoms listed, be sure to schedule an appointment with your physician.
Specific symptoms of brain cancer may include:
- Aching or pressure in the head area
- Altered perception of touch or pressure; such as confusion with right and left sides of the body
- Changes in vision, including partial vision loss or double vision
- Difficulty with fine motor skills
- Extreme changes in judgment, motivation, or sluggishness
- Hard time swallowing, along with weakness or numbness in the face
- Muscle weakness or paralysis
- Sudden changes in speech, hearing, memory, or emotional state
- New growths in hands and/or feet
- Unexplained loss of balance
- Unexpected lactation (secretion of breast milk) or changes in menstrual periods, in women
Detection and Diagnosis of Brain Cancer
Doctors use a variety of tests to detect and diagnose brain tumors. These tests can also show what type of brain tumor it is and if it has spread to other parts of the body. Your doctor may also run certain tests to determine the most effective course of treatment.
Brain Tumor Imaging Tests
Imaging tests are the primary method for detecting and diagnosing a brain tumor. They can also show if the tumor is a primary brain tumor or if it is cancer that has spread to the brain from another location within the body. Imaging diagnostic tests typically include:
- Magnetic Resonance Imaging (MRI), a test that uses magnetic fields to produce detailed images of the body
- Computed Tomography (CT) scan, which creates a 3-D picture of the inside of the body using X-rays taken from different angles
- Positron Emission Tomography (PET) or PET-CT scan, a test that creates pictures of organs and tissues using various substances, such as sugars or proteins
- Cerebral arteriogram, which is an X-ray (or series of X-rays) of the head that shows the arteries in the brain
Other diagnostic tests your doctor may perform to determine if a brain tumor is present can include:
- Lumbar puncture or spinal tap, which looks for tumor cells, blood, or tumor markers in the cerebrospinal fluid (CSF)
- Myelogram, a test used to find out if the tumor has spread to the spinal fluid, other parts of the brain, or the spinal cord
- Molecular testing of the tumor, which is used to identify specific genes, proteins, and other factors like tumor markers, that are unique to the tumor
- Neurological, vision, and hearing tests to see if a tumor is affecting brain functions
- Neurocognitive assessment, which is a detailed assessment of all major brain functions, including storage and retrieval of memory, language abilities, dexterity, calculation, and the patient’s overall well-being
- Electroencephalography (EEG), a noninvasive test in which electrodes are attached to the outside of the patient’s head to measure electrical activity of the brain
- Evoked potentials, which use electrodes to measure the electrical activity of important nerves that could be affected by a growing tumor
Various factors, including the type of brain tumor suspected, signs and symptoms, your age, current medical condition, and previous test results, are all considered when choosing a diagnostic test.
If imaging tests show there may be a brain tumor, the next step would be to perform a biopsy, which is taking a sample of the possible tumor. The sample of tissue will then be tested in a laboratory.
In most cases, brain tumors are not diagnosed until after the patient is experiencing symptoms. An internist or neurologist typically gives the initial diagnosis.
Types of Brain Tumors
According to the National Brain Tumor Society, there are more than 130 different types of brain tumors, many with their own multitude of subtypes.
Common Types of Brain and Spinal Tumors
There are two more common types of brain and spinal tumors that can occur in adults.
- Meningiomas, which originate in the meninges, the layers of tissue that surround the outer part of the brain and spinal cord
- Gliomas, which originate in the glial (supportive) tissue
Less Common Types of Brain and Spinal Tumors
Less common tumors, which either account for a very low percentage of brain and spinal tumors, or are more common among children than adults, may include:
- Astrocytomas are tumors that start in glial cells called astrocytes. About two out of ten brain tumors are astrocytomas.
- Schwannomas, which develop from Schwann cells – cells that surround and insulate cranial nerves – account for about 8% of all primary brain tumors.
- Oligodendrogliomas, which start in brain glial cells called oligodendrocytes. About 4% of primary brain tumors are oligodendrogliomas.
- Ependymomas, which are tumors that start in the ependymal cells that line the ventricles. They account for 2-3% of primary brain tumors.
- Medulloblastomas, which are tumors that develop from neuroectodermal cells (early forms of nerve cells) in the cerebellum. Medulloblastomas occur much more often in children than in adults.
- Gangliogliomas, which are slow growing tumors that contain both neurons and glial cells. These tumors are very uncommon in adults.
- Craniopharyngiomas, which start above the pituitary gland but below the brain. Craniopharyngiomas are more common in children, but they are sometimes seen in adults.
- Chordomas, which are rare tumors that start in the bone at the base of the skull or at the lower end of the spine. Although they don’t start in the central nervous system, they can injure the nearby brain or spinal cord by pressing on it.
- Non-Hodgkin lymphomas, which starts in the white blood cells called lymphocytes (a primary cell type of the immune system). These lymphomas are more common in people with immune system problems, such as those infected with HIV, the virus that causes AIDS. However, in recent years, these lymphomas have become less common because of new treatments for AIDS.
- Pituitary tumors, which start in the pituitary gland. In most cases, pituitary tumors are benign, slow-growing masses that represent about 10% of primary brain tumors.
Staging Brain Cancer
Unlike other cancers, brain cancer is assigned a “grade” rather than a stage, based on how the cells look under the microscope. The most commonly used brain cancer grading system, developed by the World Health Organization (WHO), is as follows:
- Grade I: Tumors are typically slow-growing and localized (not growing into nearby tissue). Grade I tumors can often be cured with surgery.
- Grade II: Tumors are slow-growing, but invasive to nearby brain tissue. Grade II tumors have a higher chance of recurrence (come back) and can change into a faster-growing tumor over time.
- Grade III: Tumors are visibly abnormal under the microscope and can grow into nearby brain tissue. Often, other treatments (in addition to surgery) are needed.
- Grade IV: Tumors are the fastest growing and typically require aggressive treatment.
Care and Treatment for Brain Tumors
When it comes to brain tumor care, a team consisting of different types of doctors work together to design a treatment plan for the patient. The treatment plan often includes a combination of treatments. This team of medical professionals is called a multidisciplinary team.
Brain cancer treatment options and recommendations depend on several factors, including:
- The size, type, and grade of the tumor
- Whether or not the tumor is pressing on other vital parts of the brain
- Potential side effects
- The preferences of the patient as well as their overall health
Your multidisciplinary team will take all these factors into consideration before you are presented with a recommended treatment plan and start date.
Brain Tumor Treatment Options
The most common treatment options for brain tumors include surgery, radiation therapy, chemotherapy, targeted therapy, and active surveillance.
Surgery is typically the first step in brain tumor treatment, especially if the entire tumor can be removed. Surgical procedures involving the brain require a craniotomy, which is the removal of part of the skull. Once the tumor is removed, the opening in the skull will be covered with the patient’s own bone.
Several advancements have been made regarding brain surgery, which include:
- Cortical mapping, which allows doctors to identify areas of the brain that control the senses, language and motor skills.
- Enhancing imaging devices, such as Image Guided Surgery (IGS), which help surgeons plan and perform surgery more accurately.
- 5 aminolevulinic acid, a fluorescent dye, which gets absorbed by tumor cells, making them more visible during surgery.
In addition to removing or reducing the size of the brain tumor, surgery provides an opportunity for biopsy, which is needed for diagnosis. For cancerous tumors that cannot be cured, removing it can still benefit the patient in that it can relieve symptoms caused by pressure on the brain.
In some cases, the location of the tumor makes it impossible to perform surgery (inoperable). If the tumor is inoperable, other treatment options will be recommended.
Radiation therapy (also called radiotherapy) is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. It is typically given after surgery and sometimes in combination with chemotherapy.
The most common type of radiation treatment is called external-beam radiation therapy, which is given from a machine outside the body. It can be directed at the tumor in a variety of ways, including:
- 3-dimensional conformal radiation therapy
- Intensity modulated radiation therapy (IMRT)
- Stereotactic radiotherapy, a technique that precisely focuses beams of radiation to destroy certain types of tumors often resulting in a greater amount of spared normal tissue.
Chemotherapy (chemo) is a group of medicines used to treat cancer. These drugs are usually given into a vein (IV) or taken orally (by mouth). Many chemo drugs, however, aren’t able to cross the blood-brain barrier and enter the fluid that surrounds the brain and spinal cord. Because of this, your oncologist may suggest another alternative, called intrathecal chemotherapy. In intrathecal chemotherapy, an anticancer drug is injected into the fluid-filled space to kill cancer cells there.
While receiving active treatment, patients are monitored every 2 to 3 months with a brain MRI. The grade of the tumor typically determines how often MRI scans are needed after treatment.
Targeted therapies are drugs or other substances that target the specific genes, proteins, or tissue of a tumor. They differ from chemotherapy in that they can identify cancerous cells and attack them, while leaving the normal, healthy cells alone.
Anti-angiogenesis therapy is commonly used for brain tumors because it “starves” the tumor of nutrients that cause it to grow and spread. Other targeted therapies for brain cancer are being researched.
Active surveillance includes closely watching a patient’s brain tumor(s) but not giving any treatment unless there are changes in test results that show the condition is getting worse. Active surveillance may be used to avoid or delay the need for treatments such as radiation therapy or surgery, which can cause side effects or other problems. During active surveillance, certain exams and tests are done on a regular schedule. Active surveillance may be used for very slow-growing brain and spinal tumors that do not cause symptoms.
Our cancer care team is here to answer any questions you have about your individual situation. Once a treatment plan is in place, our staff is here to help you or your loved one through every step of cancer treatment.
Many clinical trials evaluating new therapies, such as proton therapy and biological therapy, as well as potential drugs to treat brain tumors, are ongoing. If you would like more information, you may speak with your oncologist regarding the available clinical trials, or you can visit our available cancer clinical trials page.
Causes, Risk Factors, and Prevention
Primary brain tumors begin in the brain itself or in surrounding tissues, such as the brain-covering membranes (meninges), cranial nerves, pineal gland, or pituitary gland. When normal cells mutate, they grow and divide at increased rates, resulting in a mass of abnormal cells, which form a tumor.
Most brain tumors are not linked with any known risk factors. However, there are a few factors that can raise the risk.
Risk factors for brain tumors may include:
- Compromised immune system, which can increase the risk of developing lymphomas of the brain.
- Radiation exposure, which is most often from radiation therapy to treat another condition. Imaging tests that use radiation (X-rays, CT scans) could possibly increase the risk, but it is not known for sure.
- Family history, although this is very rare. Von Hippel-Lindau disease, Li-Fraumeni syndrome, Tuberous sclerosis, and Neurofibromatosis (NF1 and NF2) are inherited conditions that have been found in families with a history of rare brain tumors.
Making healthier lifestyle changes (i.e. quitting drinking and smoking) can help reduce the risk of many cancers in adults, including lung and breast cancers. Regarding brain tumors, however, there are no known lifestyle-related or environmental risk factors other than radiation exposure.