Chordoma Foundation

Glossary

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 heart beat.

Cancer: Cancer is a term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems.

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

Carotid: 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.

Chondrosarcoma: Chondrosarcomas are malignant tumors of cartilage cells that occur in or near the bones.

Clivus: The clivus is a bone located in the center of the head, below the pituitary gland, in front of the brainstem and behind the sinuses.

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

Conventional Chordoma: Conventional chordoma is the most common form of chordoma. It is composed of a unique cell type that looks like notochord and is usually easily distinguished from chondrosarcoma. Conventional chordomas can have small areas of chondroid or dedifferentiated appearance.

Cytotoxic: Cytotoxic chemotherapy agents are drugs selectively damage or destroy rapidly growing cells.

Dura: The dura is a water balloon-like sheath that covers the brain and spinal chord and encloses cerebral-spinal fluid.

Extra-axial: Extra-axial means not involving the spinal axis. Extra-axial chordomas have been reported in multiple locations.

First-line treatment: First-line treatment is a medical therapy recommended for the initial treatment of a disease

Gene: A gene is 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 three histological subtypes of chordoma appears different under the microscope, allowing pathologists to distinguish between them.

IMRT: Intensity-modulated radiation therapy (IMRT) is a type of radiotherapy that utilizes 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: Incidence is the number of new events occurring in a defined population within a particular time period. For example, in the United States the incidence is approximately 300 new chordomas per year or, one new chordoma per million people per year.

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

Intraosseous: Intraosseous means inside the bone. Most chordomas begin inside of bones in the skull and spine and extend outwards as they grow.

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

Lumbar spine: The lumbar spine consists of the five vertebrae of the lower back.

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

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

Median: Median is the midpoint in a set of numbers. There are an equal number of values above and below the median.

Metastasize: To metastasize means to spread from one part of the body to another. Local metastasis means spreading to areas surrounding the original tumor. Distant metastasis means spreading to non-adjacent organs such as the liver or lungs.

Mutation: A mutation is 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 (germ-line mutation) or can occur spontaneously in individual cells of the body (somatic mutation).

Negative margins: The goal of cancer surgery is to remove the tumor and a surrounding region (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.

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

Notochord: The notochord is a stiff rod-like structure of cells that is found in all vertebrate embryos. During development, the vertebral column forms around the notochord, and the notochord simultaneously disappears. The notochord does not turn into bone, but pieces of notochord can become lodged in developing 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: Off-label use is the practice of prescribing drugs for a purpose other than the drug’s approved indication. For example, treating chordoma with a drug approved to treat lung cancer would be considered off-label use.

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

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

Outcome: Outcome refers 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.

Prevalence: Prevalence refers to the number of people living with Chordoma in a defined population. Prevalence can be calculated by multiplying the incidence by the survival time.

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 extraosseous (outside-the-bone) chordomas.

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

Proliferation: Proliferation of tumor cells means growth and division. 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.

Sacrum: The sacrum consists of five vertebrae at the base of the spine near the pelvis, and between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx (tailbone).

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

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

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

Sporadic: Sporadic is 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: Radiosurgery is a type of radiation therapy that delivers a high dose of radiation to a tumor in a short period of time. Just like other forms of radiation, it kills tumor cells by damaging their DNA and preventing them from replicating. Stereotactic radiosurgery precisely delivers radiation to a tumor using radiation beams from different angles.

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

Thoracic spine: The thoracic spine consists of the twelve vertebrae of the upper and mid back, extending from the shoulders to the bottom of the rib cage.

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