This glossary contains definitions of terms you may encounter relating to childhood cancer, or that you may come across on this blog.


Absolute Neutrophil Count: Abbreviated as ANC. The percent of neutrophils multiplied by the total number of white blood cells. This number is used to define neutropenia.

Amnestic: Unable to remember; a term often used to refer to a characteristic of some sedation/anesthetic drugs.

Analgesia: A medication administered to reduce pain.

Anaplasia: Cells or group of cells that grow without structure; a term often used to describe cancer cells.

ANC: See absolute neutrophil count.

Anaemia: Low number of red blood cells in the blood, reported as a low hemoglobin or low hematocrit. Decreased number of red blood cells may cause symptoms including tiredness, shortness of breath, and weakness.

Anaesthesia: Medication—intravenous, gaseous, local, or spinal—administered to provide pain relief and/or unconsciousness during surgery.

Anaesthesiologist: A physician specializing in the study and administration of anesthetic medications and the care of patients before, during, and after anesthesia.

Anaesthetist: A person who administers anesthesia—often a nurse with advanced training in this specialty.

Angiography: A diagnostic procedure performed in the radiology department to visualize blood vessels after introduction of a contrast material (dye) into an artery.

Anticonvulsant: Medication used to treat or prevent seizures.

Antiemetic: Medication used to stop nausea and vomiting.

Antineoplastic: Another term for chemotherapy drugs.

Aphasia: Difficulty with understanding or expressing language, often but not exclusively due to damage in the cerebral cortex.

Ataxia: Inability to coordinate movements or balance; clumsiness.

Attending Physician: A physician who has completed training in a particular specialty.

Audiologist: A person who tests hearing.


Benign Tumour: Slow-growing, nonmalignant tumor that does not spread to other parts of the body

Benzodiazepine: A medication used to sedate, to control anxiety, and to stop seizures.

BID: Abbreviation for the Latin term bis in die, meaning “twice a day.”

Biopsy: Examination of a small amount of tissue by a pathologist in an attempt to identify the tumor type.

Blood–Brain Barrier: A protective barrier formed by blood vessels and glial cells that prevents some substances in the blood from entering the brain.

Bone Marrow Transplant: A procedure in which healthy cells able to produce the components of blood are given to a patient to begin producing new blood cells for the patient. This is in contrast to a stem cell transplant by virtue of where the donor cells come from. Cells for bone marrow transplants are usually removed (or harvested) from the pelvic bone.

Brachytherapy: A system of treatment in which radioactive substances are placed near or in the brain tumor.

Brainstem: The bottom part of the brain that controls many of the automatic functions of the body (breathing, heartbeat, and so on).

Broviac: A specific type of tubing that is placed through the chest wall into a large blood vessel.

Burr Hole: A surgical small round hole made in the skull usually made for shunt placement and some other neurosurgical issues.


Cancer: A group of diseases in which malignant cells grow out of control and spread to other parts of the body.

CAT scan (CT scan): A test using computers and X-rays to create images of various parts of the body

CBC: Abbreviation for complete blood count.

Centigray: Abbreviated as cGy. A unit of measurement in radiation.

Central Nervous System: Abbreviated as CNS. The CNS is the nervous system consisting of the brain and spine.

Cerebellar Astrocytoma: A benign glial tumor of the cerebellum.

Cerebellar Mutism: A problem that most commonly occurs in some cases of surgery within the posterior fossa where the patient has extreme difficulty coordinating movements of the mouth. The patient may lose the ability to speak and eat. Generally, all patients with this problem recover functional speech.

Cerebellum: The portion of the brain that coordinates movements and balance.

Cerebrospinal Fluid: Abbreviated as CSF. The clear fluid made in the ventricular cavities of the brain that bathes the brain and spinal cord. It circulates through the ventricles and the subarachnoid space.

cGy: See centigray.

Chemotherapy: Medications used to destroy tumor cells; may be given by mouth, intravenously, or intrathecally.

Child Life Specialist: A professional who uses play therapy and develops activities to help children cope with the effects of illness and treatment.

Children’s Oncology Group: Abbreviated as COG. A group of over 240 medical centers in North America with the primary objective of conducting clinical trials and ensuring that children have access to high-quality medical care.

Choroid Plexus Papilloma: A tumor arising in the choroid plexus, the part of the ventricles in the brain that produces cerebrospinal fluid. This type of tumor usually arises in infants.

Clinical Trial: A research protocol used to try to identify the most effective treatment. Most children with tumors are participating in clinical trials. These are designated as phase 1, phase 2, or phase 3 trials.

CNS: See central nervous system.

COG: See Children’s Oncology Group.

Cognition: A general term involving perceiving, recognizing, conceiving, judging, sensing, reasoning, remembering, and imaging.

Computed Tomography Scan: Abbreviated as CT scan. An x-ray device linked to a computer that produces cross-sectional images of the body. Contrast dye may injected into a vein to make some abnormal tissue more evident.

Conformal Radiation: Abbreviated as CRT. A radiation therapy that uses computers to create a three-dimensional picture of the tumor so that multiple radiation beams can be shaped exactly (can conform) to the contour of the treatment area.

Corticosteroids: Drugs used to decrease swelling (edema) around tumors.

Craniotomy: Any surgical opening into the skull (cranium).

Cranial Nerves: Twelve pairs of important nerves that originate in the brain and control special senses of hearing, taste, sight, and smell as well as facial, tongue, and eye movement and the skin sensation of the face.

Craniopharyngioma: Nonglial growth that usually causes growth failure because of its location near the pituitary gland. It often affects vision.

CRT: See Conformal Radiation.

CSF: See Cerebrospinal Fluid.

CT scan: See Computed Tomography Scan.

Cyst: A cavity, usually filed with a fluid, sometimes associated with tumors.


Diabetes Insipidus: A problem with water balance in the body due to a dysfunction of the pituitary gland that causes excess urine production and great thirst.

Diplopia: Double vision.

Dura: Tough outer membrane covering the brain.

Dysarthria: Impairment of the ability to articulate words, a symptom that may occur with tumors located in the medulla of the brain.

Dysmetria: A tremor or unsteadiness of the arms often tested by having the patient alternate pointing to his or her nose and then to the physician’s finger.

Dysphagia: Difficulty in swallowing. This symptom usually indicates a tumor involving the lower brainstem/cranial nerves.

Dysphasia: Impaired speech with difficulty or inability to put words in their proper order, a symptom that may occur with tumors located in the dominant cerebral hemispheres, particularly the temporal and parietal lobes.


Ecchymosis: Bruises.

Edema: An excessive accumulation of fluid in the cells or tissues that results in swelling.

EEG: See Electroencephalogram.

Electroencephalogram: Abbreviated as EEG. A test that measures the electrical activity in the brain, particularly in evaluating activity in areas that might indicate seizures.

Electrolytes: Elements in the blood that affect cells and can be tested for by blood chemistry analysis. These include sodium, potassium, chloride, and bicarbonate.

Encapsulated:  Refers to a tumor that is localized, or wholly confined to a specific area, surrounded by a capsule.

Endocrinologist: A doctor who is trained to diagnose and treat disorders of the endocrine glands. (These glands secrete hormones that effect many body functions).

Endotracheal Tube: A breathing tube placed in the mouth that goes into the trachea.

Ependymoma: Tumor that arises from cells that line the passageways in the brain where cerebrospinal fluid is produced and stored. Ependymomas are either supratentorial (occurring in the top of the head) or infratentorial (occurring in the back of the head). Most ependymomas in children are infratentorial, located in or around the fluid-filled fourth ventricle.


Fellow: A physician who is in the process of training in a specialized field.

Fine-needle Aspiration: A procedure in which a needle is inserted, under local anesthesia, to obtain a sample for the evaluation of suspicious tissue

FMRI: See Functional Magnetic Resonance Imaging.

Functional Magnetic Resonance Imaging: Abbreviated as fMRI. A scanning technique used to show brain function by demonstrating changes in the chemical composition of brain areas or changes in the flow of fluids.


G-CSF: See granulocyte colony-stimulating factor.

G Tube: See gastrostomy tube.

Gadolinium: The contrast material used for magnetic resonance imaging.

Gamma Knife: The brand name for a device that a surgeon uses to perform stereotactic surgery.

Gastrostomy Tube: Abbreviated as G tube. A tube used for feeding that goes through the abdominal wall and into the stomach.

Germ Cell Tumour: Tumor arising in the pineal or suprasellar regions, above the pituitary gland. This type of tumor is most often diagnosed around the time of puberty and is more likely to affect boys than girls.

Glial Cell: A general name for cells of the central nervous system that nourish and support the nerve cells and the blood vessels that supply the nervous system. There are several specific types of glial cells: astrocytes, ependymal cells, and oligodendrocytes.

Glioma: A tumor arising from glial cells or the supporting cells of the nervous system.

Gold Ribbon: The symbol of childhood cancer.

Grade: When related to a tumor, it reflects the (high or low) potential for growth and degree of anaplasia.

Granulocyte Colony-Stimulating Factor: Abbreviated as G-CSF. A medication given by injection to stimulate white blood cell production.

Grey: Abbreviated as Gy. A unit of measurement in radiation; can be used interchangeably with rad.

Grey Ribbon: The symbol for brain tumors.

Gross Total Resection: Complete removal of a tumor as measured by the surgeon’s observation (not by a microscope).

Gy: See Gray.


Health Care Professional: Any medical team member involved in your care, such as a nurse, physician, physiotherapist, occupational therapist, social worker, or psychologist.

Haematocrit: A measurement of red blood cells in the blood; often used as the basis for decisions regarding transfusions.

hematoma: A collection of blood most commonly under the skin.

Hemiparesis: Muscle weakness of one side of the body.

Hemiplegia: Complete paralysis on one side of the body.

Haemoglobin: A measurement of red blood cells in the blood; often used as the basis for decisions regarding transfusions. This a number approximately one third of the hematocrit.

Hickman: A specific type of tubing placed through the chest wall and into a large blood vessel.

Home Care: A hospital department or organization designed to provided equipment, support, and nurses so that medical care can be undertaken at home.

Hormone: A substance that the body produces that acts as a messenger to affect other organs.

Hospice: Organizations that specialize in end-of-life care.

Hydrocephalus: “Water on the brain”; a buildup of abnormal amounts of cerebrospinal fluid within the brain’s ventricular system that causes pressure on the brain.

Hyperfractionated Radiation Therapy: The administration of radiation therapy in smaller and more frequent doses to equal the total prescribed amount.

Hyper-: A prefix to medical words that means “high” or “elevated.”

Hypertension: Elevated (high) blood pressure.

Hypo-: A prefix to medical words that means “low.” Hypotension: Low blood pressure.

Hypotonic: Floppy; low muscle tone.

Hypoxia: Low level of oxygen in the blood.


ICP: See Intracranial Pressure.

IM: See Intramuscular.

Immune System: The body’s defense system that protects it from harmful foreign substances such as bacteria and viruses.

Immunotherapy: Using the body’s own defense system (antibodies, white blood cells, and so forth) to combat a tumor.

IMRT: See Intensity-Modulated Radiation Therapy.

Infratentorial: The bottom portion of the brain (located in the posterior fossa under the tentorium) consisting of the cerebellum and brainstem.

Intensity-modulated radiation therapy: Abbreviated as IMRT. A three-dimensional computer-aided radiation therapy that targets treatments at the tumor, decreasing damage to normal tissue.

Intern: This term usually applies to a physician who is in the first year of training after medical school.

Intracranial pressure: Abbreviated as ICP. Pressure within the head; if it increases, it causes pressure on the brain.

Intramuscular: Abbreviated as IM. Injection into a muscle.intrathecal: Injection into the cerebrospinal fluid.

Intravenous: Abbreviated as IV. Injection into a vein.

Intubation: The placement of a tube in the trachea (windpipe) to assist with breathing.

Invasive: Refers to something that invades tissue, including tumors, procedures, and medical specialties (such as invasive radiology, which often places intravenous catheters).

IV: See intravenous.


Lamina: A thin, flat layer of membrane that is the bony arch of a vertebra.

Laser: A technique using focused light to evaporate tumors during surgery

Leptomeningeal: Most commonly used to describe spread of the cancer to the tissue lining around the brain.

Lesion: A lump or abscess that may be caused by injury or disease, such as cancer.

Leukocyte: A white blood cell.

Long-Term Follow-Up Clinic: Abbreviated as LTFUC. A specialized clinic that works with survivors and their families to provide comprehensive care, education, and counseling.

LP: See Lumbar Puncture.

LTFUC: See long-term follow-up clinic.

Lumbar Puncture: Abbreviated as LP; also called a spinal tap.A needle penetrates the subarachnoid space of the lumbar spine and a sample of spinal fluid is withdrawn for laboratory examination. This procedure can also be used to inject dye prior to myelography or to administer medication.

Lymph nodes: Hundreds of small oval bodies that contain lymph. Lymph nodes act as our first line of defense against infections and cancer.


Magnetic Resonance Imaging: Abbreviated as MRI. A scanning technique used to diagnose and monitor brain tumors. With this technique, magnetic fields, rather than radiation, are used to make a picture of an area of the body.

Malignant: A tumor made up of cancer cells of the type that can quickly spread to other parts of the body, causing harm to surrounding and/or distant tissue.

Medical Student: A person in medical school training to become a physician.

Medulloblastoma: The most common malignant brain tumor in children, typically arising in the middle of the cerebellum, interfering with the flow of cerebrospinal fluid and causing hydrocephalus.

Meninges: The covering membranes of the brain consisting of the dura mater, the arachnoid, and the pia mater.

Meningitis: Infection or inflammation of the membranes (meninges) that cover the brain and spinal cord.

Metastasis: The spread of tumor cells of disease from one part of the body to another.

Midbrain: A part of the brain between the pons and the cerebral hemispheres in the brainstem.

MRI: See Magnetic Resonance Imaging.

Myelogram: An x-ray procedure by which a dye is injected into the spinal column to show any pathology of the spinal cord.


Narcotic: A class of medication used for pain management.

Necrosis: Dead cells or tissue.

Nasogastric Tube: Abbreviated as NG tube. A tube from the nose into the stomach often used for feeding but sometimes used to remove gastric fluids.

Nasojejunal Tube: Abbreviated as NJ tube. A tube, used for feeding, that goes from the nose to the part of the intestines called the jejunum.

Neoplasm: A tumor, either benign or malignant.

Neurologist: A doctor specializing in the diagnosis and treatment of disorders and diseases affecting the brain, spinal cord, and peripheral nerves.

Neuro-Oncologist: A physician who specializes in the treatment of cancer and tumors affecting the brain and spinal cord.

Neuro-Ophthalmologist: A doctor specializing in the diagnosis and treatment of eye problems that are a result of damage to the brain.

Neuropsychologist: A psychologist who specializes in the effects that injury to or diseases of the brain and spinal cord have on emotions, behavior, and learning.

Neurosurgeon: A surgeon specialized in the diagnosis, treatment, and surgical management of disorders and disease of the brain, spine, and nervous system.

Neutrophil: A type of white blood cell that fights infections. Neutrophils may also be referred to as segs or polys.

Neutropenia: A low number of neutrophils in the blood, placing the patient at increased risk for infection.

NG tube: See Nasogastric Tube.

NJ tube: See nasojejunal tube.

Nurse Practitioner or Specialist: A specially educated nurse who provides direct care for your child in collaboration with your child’s physician.

NPO: Abbreviation for the Latin term non per os, meaning, literally, “nothing through the mouth.” It is used to mean “nothing to eat or drink.”

Nystagmus: A particular movement of the eye.


Occupational Therapist: A specially trained person who deals with certain rehabilitation issues.

Oedema: An excessive accumulation of fluid in the cells or tissues that results in swelling.

Ommaya Reservoir: A medical device implanted under the scalp that delivers medication directly into the ventricles.

Oncogenes: Fragments of genetic material (DNA) that carry the potential to cause cancer.

Oncology: The study and treatment of cancer. Doctors who specialize in oncology are called oncologists.

Oncologist: A physician who specializes in the treatment of cancer.

Ophthalmologist: A doctor who specializes in the diagnosis and treatment of visual disorders and diseases.


Papilledema: Swelling of the optic nerve usually caused by intracranial pressure that can be seen on physical examination by looking at the back of the eye with an ophthalmoscope; not an uncommon finding with brain tumors.

Paralysis: Total loss of muscle strength.

Paresis: Partial loss of muscle strength.

Paraparesis: Weakness of the legs only.

Pathologist: A doctor who specializes in the diagnosis of disorders and diseases by studying the tissues and fluids of the body.

PBTC: See Pediatric Brain Tumour Consortium.

Pediatric Brain Tumour Consortium: Abbreviated as PBTC. A group of medical centers in North America with the primary objective of conducting clinical trials and ensuring that children have access to high-quality medical care.

Peripherally Inserted Central Catheter Line: Abbreviated as PICC line. A type of intravenous catheter.

PET scan: See positron emission tomography scan.

Physical Therapist: A specially trained person who deals with certain rehabilitation issues.

Physiatrist: A doctor who has specialized training in the field of physical medicine and rehabilitation (also called PM and R).

PICC line: See peripherally inserted central catheter line.

PICU: Abbreviation for pediatric intensive-care unit.

Pituitary Gland: An endocrine gland that is situated at the base of the brain and supplies hormones that control many vital processes.

Platelet: A blood component that functions in blood clotting.

PNET: See Primitive Neuroectodermal Tumour.

PO: Abbreviation for the Latin term per os, meaning, literally, “by mouth.”

Port: A medical device implanted under the skin, usually in the chest wall, that allows access to the blood vessels to give medication and to draw blood.

Positron Emission Tomography scan: Abbreviated as PET Scan. A type of scanning used to measure activity of the brain.

Postictal: A period of sleepiness, confusion, or agitation after a seizure.

Posterior Fossa: The portion or location in the brain that includes the cerebellum, brainstem, and fourth ventricle.posterior fossa syndrome: A problem that sometimes develops after posterior fossa surgery that causes a patient to be very floppy and irritable. This an be accompanied by hemiparesis, mutism, and cortical blindness.

Primary tumor: The original cancer site. For example, breast cancer that has spread to the bone is still called breast cancer.

Primary Brain Tumour: A type of tumor that originates within the brain itself, in contrast to tumors that spread to the brain from another site in the body.

Primitive Neuroectodermal Tumour: Abbreviated as PNET. A tumor arising in the posterior fossa of the brain. (However, tumors with the same characteristics can also occur in other areas of the brain.) This type of tumor tends to spread to other areas of the brain and spinal cord.

Protocol: A written plan that specifies exact procedures to follow (related to clinical trials and therapies for brain tumors).

Proton-Beam Radiation: A specific type of radiation therapy using particle beams of protons in a very confined area of the brain.

Pulse Oximeter: A medical instrument used to measure the oxygen level in the blood by a painless lighted probe.


QID: Abbreviation for the Latin term quater in die, meaning “four times a day.”


Rad: A unit of measurement used in radiation; can be used interchangeably with a unit called the Gray (Gy).

Radiation Oncologist: A physician who specializes in the treatment of tumors by radiation.

Radiation Therapy: Sometimes also called XRT or RT. A technique used to destroy tumor cells by exposing the affected tissue to radiation. This therapy usually consists of daily sessions for several weeks.

Radiologist: A doctor who specializes in the interpretation of x-ray films and other imaging techniques.

Remission: The decrease or disappearance of clinical symptoms of disease.

Resection: Surgical removal of a tumor. See also Gross Total Resection and Subtotal Resection.

Resident: A physician who is undertaking training in a specialty.

Risk factor:Anything that increases a person’s chances of developing cancer, for example, smoking and lung cancer.


Seizure: Also called a convulsion; excitation of neurons in the brain leading to involuntary muscle contractions or sensations.

Secondary Brain Tumour: A tumor that develops away from the original site. See also Metastasis.

Sedative: Medication used to make a patient sleepy or more relaxed; often used during medical procedures.

Sepsis: An infection in the blood stream.

Setup: An initial procedure in radiation oncology in which the specific locations for radiation are determined and marked by tattoos. Radiation therapy does not take place at this time.

Shock: A serious medical condition in which organs are not receiving adequate blood flow. It is usually associated with low blood pressure.

Shunt: A plastic catheter with a reservoir and a valve used to relieve the increased intracranial pressure caused by hydrocephalus.

Side effects: Secondary effects of drugs used for disease treatment.

Simulation: A confirmation procedure in radiation therapy to ensure that the marked location is accurate.

Single-Photon Emission Tomography: Abbreviated as SPECT. A new nuclear imaging technique that involves injection of a radioisotope (radioactive substance) that the blood then carries to the brain’s tissues. Areas with more blood flow absorb more radioisotope. These areas are highlighted by colors, showing brain blood flow.

Social Worker:  A health care profession who aids patients and families in multiple aspects of non-medical care, including supportive counseling, financial aid, communication with physicians, and school issues.

Speech and Language Pathologist: A therapist trained specifically in rehabilitative issues involving communication and eating.

SPECT: See single-photon emission tomography.

Spinal Tap: See Lumbar Puncture.stem cell transplant: A procedure in which healthy cells able to produce the components of blood are given to a patient to begin producing new blood cells for the patient. This is in contrast to bone marrow transplant by virtue of where the donor cells come from. Stem cells are removed (or harvested) usually from the peripheral blood.

Steroids: Corticosteroids are medications used to control the buildup of fluid and swelling of the brain before or after surgery. Anabolic steroids are different and are used, on rare occasions, as appetite stimulants.

Stereotactic Radiosurgery: A single-dose focal radiation treatment in which many relatively weak doses of radiation are directed at a small target simultaneously, but from numerous points of the head.

Stereotactic or Stereotaxis: Computed tomography scanning and magnetic resonance imaging used to permit positioning (for surgery or radiation) in three dimensions so that a tumor can be located very precisely.

Subcutaneous: Abbreviated as SQ. Under the skin; often referring to the way shots, such as granulocyte colony-stimulating factor or growth hormone, are given.

Subtotal Resection: Less than total surgical removal of a tumor.

Supratentorial: The large top portion of the brain (above the tentorium) consisting of the cerebral hemispheres.


Thrombocytopenia: Low number of platelets.

TID: Abbreviation for the Latin term ter in die, meaning “three times a day.”

Tinnitus: Buzzing or ringing in the ear, a symptom common with tumors of the acoustic nerve. May also be a side effect of some medications.

Tracheostomy:  A hole made in the trachea in which a breathing tube is placed.

Tumour:  An abnormal overgrowth of cells. Tumors may be benign or malignant (by cell type or location).


Ultrasound: A technique using sound waves (to give a picture) that is used in the diagnosis of a wide variety of conditions.


VA shunt: See Ventriculoatrial Shunt.

Ventricles: Small fluid-filled cavities within the brain; these are the location of cerebrospinal fluid production.

Ventriculoatrial Shunt: Abbreviated VA shunt. Drains cerebrospinal fluid from the ventricles of the brain into the heart.See also shunt.

Ventriculoperitoneal Shunt: Abbreviated VP shunt. Drains cerebrospinal fluid from the ventricles of the brain into the abdominal cavity. See also shunt.

Ventriculostomy: A hole made to allow cerebrospinal fluid to drain from the ventricles. This may be external (so the fluid flows into a drain outside the body) or internal (such as a third ventriculostomy).

Vertigo: Dizziness with the sensation of spinning or moving.

Vital Signs: These are blood pressure, pulse, respiration, and temperature.

VP shunt: See ventriculoperitoneal shunt.


X-Knife: The brand name for the device that a surgeon uses to perform stereotactic surgery.

X-ray: High-energy electromagnetic radiation used to diagnose and treat disease.