Chordoma Foundation

Glossary

Angiography: An imaging test that is done before surgery to show the location of important blood vessels.

Benign: In cancer terms, tumors that do not invade and destroy nearby tissue or spread to other parts of the body.

Biopsy: A procedure that uses a needle to remove a small tissue sample from the tumor to be tested in order to make a diagnosis.

Brachytherapy: A type of radiation therapy in which a small amount of radioactive material is placed into the body to kill cancer cells.

Brachyury: A gene that makes a protein, also called brachyury, that is present at high levels in nearly all chordoma tumors.

Brainstem: The brainstem is the lower part of the brain connected to the spinal cord. The brainstem relays all signals to and from the brain and the body, and is responsible for maintaining consciousness, breathing, and heartbeat.

Carbon ion radiotherapy: Carbon ion radiotherapy is a type of particle radiation therapy that uses a beam of charged carbon particles to deliver high doses of radiation to a tumor while sparing surrounding normal tissue.

Carotid artery: The carotid artery is a major artery that provides the brain, head, and neck with oxygenated blood.

Cervical spine: The cervical spine consists of the seven vertebrae that make up the neck. These vertebrae are commonly referred to as C1-C7.

Chemotherapy: The use of drugs that spread through the body to kill cancer cells. Chemotherapy typically refers to drugs that kill fast-growing cells.

Chondroid: One of the four histological types of chordoma, this term was more commonly used in the past when it was difficult to tell the difference between conventional chordoma and chondrosarcoma. Chondroid chordomas behave the same and are treated the same as conventional chordomas.

Chondrosarcoma: Malignant tumors of cartilage cells that occur in or near the bones.

Clinical trials: Research studies that are done to test whether a treatment is safe and effective for patients with a specific disease, or specific type of disease.

Clivus: The surface of a portion of bone at the base of the skull. It is surrounded by the brainstem and both carotid arteries. Chordomas that form in this area are called clival chordomas.

Coccyx: The final segment of the human vertebral column, commonly called the tailbone. It consists of 3 to 5 fused vertebrae below the sacrum.

Conventional chordoma: The most common histological subtype of chordoma, also called classic chordoma. It is composed of a unique cell type that looks like notochord cells, and can show areas of chondroid dedifferentiation.

Computed tomography (CT) scan: A type of imaging scan that is used to help diagnose chordoma. CT scans can also be used to help guide the needle during a biopsy. They are sometimes referred to as “CAT” scans.

Conformal radiation: Types of radiation that can focus the beams of radiation on the tumor, while minimizing the amount of radiation that reaches the surrounding healthy tissue.

Cytotoxic chemotherapy: The use of anti-cancer drugs that damage or destroy rapidly growing cells.

Dedifferentiated: A histological subtype of chordoma that is more aggressive and usually grows faster than conventional chordomas. Dedifferentiated chordomas occur in only 5 percent of patients, can have loss of the INI-1 gene, and are more common in pediatric patients.

Diffusion MRI (D-MRI): A type of MRI which can help doctors tell the difference between chordoma and chondrosarcoma, in order to make a correct diagnosis.

Drug therapy: The use of treatments like targeted therapies and immunotherapies to kill cancer cells.

Dura: A water balloon-like sheath that covers the brain and spinal cord and encloses cerebral-spinal fluid.

En-bloc: During surgery, removal of the tumor in one piece without cutting it into smaller pieces.

External beam radiation: Radiation that is delivered from outside the body.

Extra-axial: Tumors that do not involve the axial skeleton, which includes the skull bones, sternum, rib cage, middle ear bones, and the vertebrae. Extra-axial chordomas, though uncommon, have been reported in multiple locations throughout the body.

Extra-osseous: Occurring outside the bone.

Fraction: The dose of radiation delivered during a session of a radiation therapy.

Gene: A segment of genetic material (DNA) that has a particular function. Humans have approximately 25,000 different genes. We receive a copy of every gene from each parent, meaning that we have two copies of every gene. Every cell in the body has the same set of genes, however, different genes are turned on in different tissues, and at different times.

Histological subtypes: Histology is the study of thin slices of tissue under a microscope. Each of the four histological subtypes of chordoma appears different under the microscope, allowing pathologists to distinguish between them.

Hypofractionation: A radiation treatment technique that gives larger doses of radiation over a smaller number of sessions. The total amount of radiation given is less than when standard fractionation is used, but the effect is the same.

Image guidance: The use of frequent imaging, such as MRI or CT, during radiation treatments to help direct the radiation to the right place.

Immunotherapy: Drug treatments that are designed to teach the immune system how to find and destroy cancer cells.

Intensity-modulated radiation therapy (IMRT): A type of radiotherapy that uses computer-controlled x-ray accelerators to deliver precise radiation doses to a specific location in the body. The radiation dose is designed to conform to the three-dimensional (3-D) shape of the tumor by modulating (controlling) the intensity of the radiation beam to focus a higher radiation dose to the tumor while minimizing radiation exposure to surrounding normal tissues.

Incidence: The number of new events occurring in a defined population within a particular time period. For example, in the United States the incidence of chordoma is approximately 300 new diagnoses per year, or one in one million people per year.

Inherited: Inherited traits are passed down from parents to offspring.

Intra-osseous: Occurring inside the bone. Most chordomas begin inside bones in the skull and spine and extend outwards as they grow.

Local control: Preventing a tumor from growing back or returning in the same spot after surgery. Chordomas typically return locally rather than spread distantly.

Local recurrence: Re-growth of the tumor in the same location after treatment.

Lumbar spine: The five vertebrae of the lower back, commonly known as L1-L5.

Magnetic resonance imaging (MRI): A type of imaging scan that is used initially to help diagnose chordoma, as well as during follow up to check for recurrence or metastasis.

Malignant: In cancer terms, tumors that can invade and destroy nearby tissue and spread to other parts of the body, making them life threatening.

Margins, surgical margins: The healthy tissue surrounding the tumor that is taken out along with the tumor to make sure that no cancer cells are left behind. Wider tumor-free margins mean a lower chance of recurrence.

Maximal resection: A surgery that has removed as much of the tumor and surrounding tissue as possible.

Metastatic: When cancer has spread to other parts of the body it is called metastatic. The process of spreading is called metastasis. The tumors that occur beyond the site of the original tumor are called metastases.

Mobile spine: The parts of the spine not including the sacrum. These include the cervical spine (neck), thoracic spine (upper back), and lumbar spine (lower back).

Multidisciplinary care: Treatment that involves a team of physicians from the various disciplines. In the case of chordoma, these disciplines include sarcoma or bone pathology, radiology, spine surgery or skull base surgery, otolaryngology, radiation oncology, medical oncology, and palliative care.

Mutation: A change in the genetic information (DNA) in a cell. Mutations occur every day all over the body and are usually harmless. Most mutations are repaired by sophisticated mechanisms within the cell. Mutations in certain genes can cause cells to grow out of control and invade other tissue, resulting in cancer. Mutations that cause cancer can be inherited from one’s parents or can occur spontaneously in individual cells of the body.

Negative margins: The goal of cancer surgery is to remove the tumor and an area (margin) of normal tissue around the tumor. A negative margin means that the entire area of surrounding normal tissue (the margin) is free of detectable tumor. Microscopic tumor cells may still be present even if a negative surgical margin is achieved.

Neurophysiological monitoring: The use of devices during surgery to monitor the functioning of neural structures such as the spinal cord, nerves, and brain. This is done to guide the surgeon during the operation, and to reduce the risk of damage to the patient’s nervous system.

Neurosurgeon: A highly-trained doctor who specializes in surgery involving the nervous system, including the brain, brainstem, spinal cord, and nerves.

Notochord: The tissue in a fetus that acts as the building blocks for the spine. The notochord disappears when the fetus is about 8 weeks old, but some notochord cells are left behind in the bones of the skull and spine.

Occult: Occult refers to tumors that are hidden or undetected, or those that are not yet symptomatic. In the case of chordoma, people may live for many years with small occult tumors without showing any signs or symptoms. Finding occult tumors before they become large and/or symptomatic can increase chances of achieving a complete resection.

Off-label use: The practice of prescribing drug treatments that are not approved by government agencies to treat a particular disease. Doctors are allowed to prescribe drugs off-label if they believe it is in the best interest of the patient.

Optic nerve: The nerve responsible for eyesight by sending signals from the eye to the brain.

Orthopedic surgeon: A highly-trained doctor who specializes in surgery involving bones. Chordomas of the spine are often treated by orthopedic surgeons.

Outcome: The health condition of a person after being diagnosed and/or treated for a particular disease. Outcome is usually measured at different time points. For example: one-, five-, or ten-year outcome.

Particle therapy: A type of external beam radiation that uses beams of protons, neutrons, or positive ions for the treatment of cancer.

Photon therapy: A type of external beam radiation that uses x-rays to kill cancer cells.

Prevalence: The number of people living with chordoma in a defined population. For example, at any given time there are fewer than one in 100,00 people living with chordoma around the world.

Primary tumor: A tumor that is found at the original site where it first arose. For example, a primary lung tumor is one that developed in the lung as opposed to one that grew elsewhere and metastasized (spread) to the lung. Chordomas are called primary bone tumors because they almost always arise from notochordal cells that are lodged in the bones of the spine and skull. Extremely rarely, chordomas can develop from notochordal remnants that do not involve the bone. These chordomas are called extra-osseous (outside the bone) chordomas.

Prognosis: A term used for a doctor’s prediction of how a patient’s disease will progress, and what chances are for recovery.

Proliferation: The growth and division of tumor cells. Most normal cells seldom divide, balancing the rate of cell division with cell death to keep a constant number of cells. Cancer cells divide rapidly and avoid death, causing an accumulation of cells and eventually the formation of a tumor.

Proton therapy, proton beam therapy: A type of particle therapy that uses beams of protons to kill cancer cells.

Radiofrequency ablation: A procedure that uses a needle to deliver energy to the tumor, causing it to heat up, and killing the cancer cells within it.

Referral center: A hospital, treatment center, or network of treatment centers where doctors have expertise in particular diseases. Patients are referred to a center based on their diagnosis.

Sacrum: The five vertebrae at the base of the spine near the pelvis, and between the two hip bones. The upper part of the sacrum connects with the last lumbar vertebra, and bottom part with the coccyx (tailbone). These bones are commonly referred to as S1-S5.

Sarcoma: Cancer of bone and connective tissue such as cartilage, fat, muscle, and blood vessels. Chordoma is a type of sarcoma.

Skull base: The bones of the skull located below and in front of the brain.

Spinal axis: The anatomical structures of the spine, spinal cord, and skull.

Sporadic: A term used to describe cancer occurring in individuals without a family history of the same type of cancer. More specifically, sporadic cancers are those not caused by an inherited high-risk genetic mutation.

Stereotactic radiosurgery: A type of radiation therapy that precisely delivers a high dose of radiation to a tumor in a short period of time, using radiation beams from different angles.

Systemic: Throughout the body, rather than confined to a specific location.

Systemic therapy: The use of drugs that spread through the body to kill cancer cells. Also called chemotherapy, or drug therapy.

Targeted therapy: A type of systemic therapy that works by blocking a specific gene or protein, or a “target”, found in a patient’s tumor cells.

Trocar CT-guided biopsy: A type of biopsy that uses a CT scanner to guide the placement of the biopsy needle. This is the type of biopsy that is recommended for chordoma to reduce the chance of spreading tumor cells.

Tumor board: A group of different types of specialists within a medical center who meet regularly to review each patient’s situation and make treatment recommendations.

Thoracic spine: The twelve vertebrae of the upper and mid back, extending from the shoulders to the bottom of the rib cage. These bones are commonly referred to as T1-T12.

Vertebrae: The bones that make up the spinal column and surround the spinal cord.