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Rewired
Minds
Let's Talk Terminology
The Rewired Minds podcast isn't a medical podcast, but we talk about brain tumors a lot. If you're new to this world, some of the terminology probably sounds like a different language.
This page breaks down the most commonly used terms in plain language. It's not exhaustive, and it's not a replacement for talking with your medical team, but it can be a starting point. Come back when you hear something unfamiliar and need it clearly explained.
For more resources and organizations that can provide deeper information, visit the Brain Tumor Resources page.
Primary Tumor Types
There are more than 120 types of primary brain and central nervous system tumors. These are the most common.
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Embryonal Tumors
Embryonal tumors are fast-growing tumors that develop from cells left over from early brain development. These tumors are most common in babies and young children.
Atypical Teratoid Rhabdoid Tumor (ATRT) - A rare and fast-growing tumor that usually affects children under age 3. It can occur anywhere in the brain or spinal cord.
Medulloblastoma - A fast-growing tumor that starts in the cerebellum, the part of the brain that controls balance and movement. It is most common in children but can occur in adults.
Primitive Neuroectodermal Tumor (PNET) - A rare, fast-growing tumor made of very young brain cells that never finished developing normally. It can develop anywhere in the brain and is most common in children and young adults.
Glioma Tumors
Glioma tumors grow from glial cells, which are the supporting cells that surround and protect nerve cells in the brain and spinal cord.
Astrocytoma - A tumor that grows from star-shaped glial cells called astrocytes. These tumors can be slow-growing or fast-growing and can occur anywhere in the brain or spinal cord.
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Diffuse Midline Glioma (DMG) - A fast-growing astrocytoma that develops in the middle areas of the brain, such as the thalamus or brainstem. It is most common in children.
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Glioblastoma (GBM) - The most aggressive and fast-growing type of astrocytoma. It is the most common malignant brain tumor in adults.
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Pilocytic Astrocytoma - A slow-growing astrocytoma that is most common in children and young adults. It often occurs in the cerebellum, the part of the brain that controls balance and coordination, and can usually be treated successfully.
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Pleomorphic Xanthoastrocytoma (PXA) - A rare, usually slow-growing astrocytoma that often occurs near the surface of the brain. It is most common in children and young adults.
Ependymoma - A tumor that grows from ependymal cells, which line the fluid-filled spaces inside the brain and spinal cord. It can block the flow of spinal fluid.
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Subependymoma - A rare, slow-growing type of ependymoma that usually causes few or no symptoms. It is most common in middle-aged and older adults.
Oligodendroglioma - A tumor that grows from oligodendrocytes, the glial cells that make the protective coating around the brain’s nerve cells. These tumors are usually slow-growing and most common in adults.
Glioneuronal and Neuronal Tumors
Glioneuronal and neuronal tumors grow from nerve cells or from a mix of nerve cells and supporting glial cells. These tumors are usually slow-growing.
Central Neurocytoma - A rare, slow-growing tumor that develops in the fluid-filled spaces deep inside the brain. It is most common in young adults and can cause headaches and problems with balance.
Dysembryoplastic Neuropithelial Tumor (DNET) - A slow-growing tumor that forms during brain development and is usually found in children and young adults. It most often causes seizures and is usually located near the surface of the brain.
Ganglioglioma - A slow-growing tumor made of both nerve cells and glial cells, which are the supporting cells that protect nerve cells in the brain. It is most common in children and young adults and often causes seizures.
Other Primary Brain Tumor Types
Acoustic Neuroma - A slow-growing, non-cancerous tumor that develops on the nerve connecting the ear to the brain. It can cause hearing loss, ringing in the ears, and balance problems.
Choroid Plexus Tumors - Tumors that grow from the choroid plexus, the tissue that makes the fluid surrounding the brain and spinal cord. These tumors are most common in children under age 2.
Craniopharyngioma - A slow-growing, non-cancerous tumor that develops near the pituitary gland at the base of the brain. It can affect hormone levels, vision, and growth in children.
Cysts - Fluid-filled sacs that can develop in the brain. Most cysts are not cancerous and may not need treatment unless they cause symptoms by pressing on brain tissue.
Germ Cell Tumor - Tumors that develop from reproductive cells that ended up in the brain during early development. They usually occur in children and teenagers and most often grow in the center of the brain.
Hemangioblastoma - A non-cancerous tumor that grows from blood vessel cells. It usually develops in the cerebellum, the part of the brain that controls balance and coordination, or in the spinal cord.
Meningioma - A usually slow-growing tumor that develops in the meninges, the protective layers of tissue covering the brain and spinal cord. It is the most common type of primary brain tumor in adults.
Pineal tumors - Tumors that develop in or around the pineal gland, a small organ deep in the brain that helps control sleep patterns. These tumors can block the flow of fluid in the brain.
Pituitary Tumors - Tumors that grow in the pituitary gland, a small organ at the base of the brain that controls hormones. Most are non-cancerous and can affect hormone levels, vision, and headaches.
Primary Central Nervous System Lymphoma - A type of cancer that starts in the white blood cells of the brain or spinal cord. It is more common in people with weakened immune systems and usually grows quickly.
Schwannomas - Non-cancerous tumors that grow from Schwann cells, which make the protective covering around nerves. These tumors can develop on any nerve in the body, including nerves in the brain.
Tumor Grades
Tumor grades describe how abnormal the tumor cells look under a microscope and how quickly the tumor is likely to grow. Lower grades grow more slowly, while higher grades grow more quickly.
Grade 1 - The tumor cells look almost normal under a microscope and grow very slowly. These tumors are the least aggressive and often have the best treatment outcomes.
Grade 2 - The tumor cells look slightly abnormal under a microscope and grow somewhat slowly. These tumors may grow into nearby brain tissue and can sometimes come back after treatment.
Grade 3 - The tumor cells look very abnormal under a microscope and grow more quickly. These tumors actively grow into nearby brain tissue and are more likely to come back after treatment.
Grade 4 - The tumor cells look very abnormal under a microscope and grow very quickly. These are the most aggressive tumors and require the most intensive treatment.
Tumor Treatments
Chemotherapy
Chemotherapy is medicine that kills cancer cells or stops them from growing. Chemotherapy can be given in different ways depending on the type and location of the tumor.
Intrathecal - Chemotherapy that is injected directly into the fluid surrounding the brain and spinal cord. This method helps the medicine reach tumor cells in these areas more effectively.
Intravenous (IV) - Chemotherapy that is given through a needle or tube placed into a vein. The medicine travels through the bloodstream to reach cancer cells throughout the body.
Oral - Chemotherapy that is taken by mouth as a pill or liquid. This allows patients to take their treatment at home rather than going to a hospital or clinic.
Wafer - Small discs containing chemotherapy medicine that are placed directly into the area where a tumor was removed during surgery. The wafers slowly release medicine over several weeks to kill any remaining cancer cells.
Clinical Trials
Clinical trials are research studies that test new treatments, drugs, or combinations of treatments to see if they work better than current options. Patients who join clinical trials get access to new therapies while helping doctors learn more about treating brain tumors.
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Immunotherapy
Immunotherapy treatment helps the body's own immune system recognize and fight cancer cells. These treatments work by boosting or changing how the immune system responds to the tumor.
CAR T-cell Therapy - A treatment that removes some of the patient's immune cells, changes them in a lab to better recognize cancer cells, and then puts them back into the patient's body to attack the tumor.
Checkpoint Inhibitors - Drugs that help the immune system attack cancer cells by blocking signals that prevent immune cells from doing their job. These medicines remove the brakes on the immune system.
Oncolytic Virus Therapy - Treatment that uses modified viruses that are designed to infect and kill cancer cells while leaving healthy cells alone. The viruses can also help the immune system recognize and attack the tumor.
Vaccines - Treatments that train the immune system to recognize and attack specific cancer cells. Unlike vaccines that prevent disease, these vaccines help treat existing tumors by teaching the body to fight them.
Integrative & Alternative Medicine
Treatments used alongside standard medical care to help manage symptoms, reduce side effects, and improve quality of life. Examples include acupuncture, meditation, massage therapy, dietary changes, exercise programs, yoga, and certain supplements. These therapies should always be discussed with your medical team before starting them.
Radiation Therapy
Treatment that uses high-energy beams to damage or kill cancer cells. Radiation can be delivered from machines outside the body or from materials placed inside the body near the tumor.
Brachytherapy - Radiation treatment where small radioactive seeds or sources are placed directly inside or very close to the tumor. This allows a high dose of radiation to reach the tumor while limiting exposure to nearby healthy tissue.
External Beam Radiation Therapy (EBRT) - Radiation treatment delivered from a machine outside the body that aims beams at the tumor. Treatments are usually given five days a week over several weeks.
Fractionated Stereotactic Radiotherapy - Very precise radiation treatment that is divided into multiple smaller doses given over several days or weeks. This accuracy helps protect healthy brain tissue while treating the tumor.
Proton Beam Therapy - A special type of radiation that uses proton particles instead of regular x-rays. Protons can target tumors more precisely and may cause less damage to healthy tissue around the tumor.
Stereotactic Radiosurgery - A very precise radiation treatment that delivers a high dose of radiation to a small area in one or just a few sessions. Despite its name, this is not actually surgery and does not require any cuts or incisions.
Whole Brain Radiation Therapy (WBRT) - Radiation treatment that targets the entire brain rather than just one specific area. This is used when cancer cells may be present in multiple locations throughout the brain.
Steroid Therapy
Medicines like dexamethasone and other corticosteroids that reduce swelling around brain tumors. These medicines can quickly relieve symptoms like headaches and improve neurological problems caused by swelling, but they do not treat the tumor itself.
Surgery
A procedure to remove all or part of a brain tumor. The type of surgery depends on the tumor's size, location, and type. Surgery can also be used to take a small sample of the tumor for testing.
Awake Brain Surgery - Surgery performed while the patient is awake and able to talk or perform tasks. This helps surgeons avoid damaging parts of the brain that control speech, movement, or other important functions.
Biopsy - A procedure to remove a small sample of tumor tissue so it can be examined under a microscope. This helps doctors determine the exact type of tumor and plan the best treatment.
Craniotomy - Surgery where an opening is made in the skull to access and remove a brain tumor. The piece of bone is usually put back in place after the tumor is removed.
Endoscopic Surgery - Surgery performed using a thin tube with a light and camera that is inserted through the nose or a small opening in the skull. This approach is most often used for pituitary tumors and tumors near the base of the skull or in the brain's fluid-filled spaces.
Laser Interstitial Thermal Therapy (LITT) - A minimally invasive procedure that uses a thin laser probe inserted through a small hole in the skull to heat and destroy tumor tissue. The procedure is guided by MRI imaging in real time.
Targeted Therapy
Drugs that work by finding and attacking specific weaknesses in cancer cells. Unlike chemotherapy that affects all fast-growing cells, targeted therapy is designed to attack only cells with certain changes or abnormalities.
Tumor Treating Fields
A treatment that uses a portable device worn on the head to deliver low-intensity electrical fields that disrupt cancer cell division. The device is worn for most of the day and is used along with chemotherapy for certain types of brain tumors.
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Watch and Wait
An approach where doctors monitor a tumor with regular scans and check-ups rather than treating it right away. This is used for slow-growing tumors that are not causing symptoms or for tumors in locations where treatment could cause more harm than the tumor itself.
Other Terms
Blood-Brain Barrier - A protective layer of tightly packed cells that surrounds blood vessels in the brain and controls what substances can pass from the bloodstream into brain tissue. This barrier protects the brain but can also make it harder for some medicines to reach brain tumors, making them challenging to treat compared to other cancer and tumor types.
Brain Metastases/Brain Mets - Tumors that started as cancer in another part of the body and spread to the brain. These are the most common type of brain tumor in adults and are treated differently than primary brain tumors. The most common brain mets are lung, breast, melanoma, kidney, and colorectal cancers.
Edema - Swelling in the brain caused by a buildup of fluid around a tumor. Edema can cause headaches, confusion, and other symptoms and is often treated with steroids to reduce the swelling.
Malignant Tumor - A cancerous tumor that grows quickly and can invade nearby tissue. Malignant tumors are more aggressive and require intensive treatment.
Methylation Testing - A lab test that looks for chemical changes on the DNA of tumor cells. These changes can help doctors predict how aggressive a tumor might be and which treatments are most likely to work.
Molecular markers - Specific genes, proteins, or other substances found in tumor cells that help doctors understand how the tumor might behave and which treatments are most likely to work. Testing for molecular markers helps create a personalized treatment plan.
Non-Malignant Tumor - A tumor that is not cancerous and typically grows slowly. These tumors do not spread to other parts of the body, but they can still cause serious problems depending on their size and location in the brain.
Primary Brain Tumor - A tumor that starts in the brain or spinal cord. These tumors develop from cells that are normally found in the brain rather than spreading from cancer in another part of the body.
Prognosis - The likely outcome or course of a disease based on the tumor type, grade, location, and how well it responds to treatment. Prognosis helps patients and families understand what to expect, though every person's situation is unique.
Recurrence - When a tumor grows back after treatment. This can happen in the same location as the original tumor or in a different area of the brain.
Resection - The surgical removal of a tumor. A complete or total resection means the entire visible tumor was removed, while a partial resection means only part of the tumor could be safely removed.
Seizure - A sudden burst of electrical activity in the brain that can cause changes in behavior, movements, feelings, or consciousness. Brain tumors can cause seizures by disrupting normal brain function.
Translational Research - Research that takes discoveries from the laboratory and turns them into new treatments that can be tested and used in patients. This type of research helps bridge the gap between scientific findings and actual medical care.
Tumor Board - A meeting where a team of different specialists, including neurosurgeons, oncologists, radiologists, and pathologists, discuss a patient's case together to recommend the best treatment plan.