Oncology Terms Glossary
Understanding cancer terminology can help you better communicate with your healthcare team and understand your diagnosis and treatment options.
A
Adjuvant Therapy
(AD-joo-vant)
Also known as: Adjuvant treatment
Treatment given after the primary treatment to lower the risk that the cancer will come back. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, targeted therapy, or immunotherapy.
Adenocarcinoma
(A-deh-noh-kar-sih-NOH-mah)
Cancer that begins in glandular (secretory) cells. Glandular cells are found in tissue that lines certain internal organs and makes and releases substances in the body, such as mucus, digestive juices, or other fluids.
Alkylating Agent
(AL-kih-LAY-ting)
A type of chemotherapy drug that works by adding an alkyl group to the DNA of cancer cells, preventing them from dividing and causing them to die. Examples include cyclophosphamide, cisplatin, and carboplatin.
Anaplastic
(A-nah-PLAS-tik)
A term used to describe cancer cells that divide rapidly and have little or no resemblance to normal cells. Anaplastic cancers tend to be aggressive.
Angiogenesis
(AN-jee-oh-JEH-neh-sis)
The formation of new blood vessels. Tumors need angiogenesis to grow beyond a certain size because they need a blood supply to bring oxygen and nutrients.
B
Benign
(beh-NINE)
Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body. They are usually not life-threatening.
Biomarker
(BY-oh-MAR-ker)
Also known as: Tumor marker, Molecular marker
A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease. Biomarkers may be used to see how well the body responds to treatment.
Biopsy
(BY-op-see)
The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue.
Bone Marrow
The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells, and platelets.
C
Carcinoma
(kar-sih-NOH-mah)
Cancer that begins in the skin or in tissues that line or cover internal organs. This is the most common type of cancer.
Chemotherapy
(KEE-moh-THAYR-uh-pee)
Also known as: Chemo
Treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. May be given by mouth, injection, or infusion.
Clinical Trial
A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease.
Complete Response (CR)
Also known as: Complete remission
The disappearance of all signs of cancer in response to treatment. This does not always mean the cancer has been cured.
D
Differentiation
Describes how much or how little tumor tissue looks like the normal tissue it came from. Well-differentiated cancer cells look more like normal cells and tend to grow and spread more slowly than poorly differentiated or undifferentiated cancer cells.
Dose-limiting Toxicity (DLT)
Side effects of a drug or treatment that are serious enough to prevent an increase in dose or level of that treatment.
E
Epithelial
(eh-pih-THEE-lee-ul)
Refers to cells that line the internal and external surfaces of the body. Epithelial cancers (carcinomas) are the most common type of cancer.
G
Grade
A description of a tumor based on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Low-grade cancer cells look more like normal cells and tend to grow slowly.
I
Immunotherapy
(IH-myoo-noh-THAYR-uh-pee)
Treatment that uses certain parts of a person's immune system to fight diseases such as cancer. This can include stimulating your own immune system to work harder or using man-made immune system proteins.
In Situ
(in SY-too)
In its original place. For example, carcinoma in situ is cancer that has not spread to nearby tissue (also called stage 0 cancer).
M
Malignant
(mah-LIG-nant)
Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.
Metastasis
(meh-TAS-tah-sis)
Plural: Metastases
The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a metastatic tumor or a metastasis.
Monoclonal Antibody
(MAH-noh-KLOH-nul AN-tih-BAH-dee)
A type of protein made in the laboratory that can bind to substances in the body, including cancer cells. Used in both cancer treatment and diagnosis.
N
Neoadjuvant Therapy
(NEE-oh-AD-joo-vant)
Treatment given before the main treatment. Examples include chemotherapy, radiation therapy, and hormone therapy given before surgery to shrink a tumor.
Neutropenia
(noo-troh-PEE-nee-uh)
A condition in which there is a lower-than-normal number of neutrophils (a type of white blood cell). This increases the risk of infection.
O
Oncogene
(ON-koh-jeen)
A gene that has the potential to cause cancer. When mutated or expressed at high levels, oncogenes can transform a normal cell into a tumor cell.
Oncologist
(on-KAH-loh-jist)
A doctor who specializes in treating cancer. Types include medical oncologists (chemotherapy), radiation oncologists (radiation therapy), and surgical oncologists (surgery).
P
Palliative Care
(PAL-ee-uh-tiv)
Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal is to prevent or treat symptoms and side effects, not to cure the disease.
Pathology
(pah-THAH-loh-jee)
The study of disease. In cancer care, pathology involves examining tissues and cells under a microscope to diagnose cancer and determine its type and grade.
Primary Tumor
The original tumor; the place where cancer began. Cancer cells can spread from the primary tumor to other parts of the body and form new (secondary) tumors.
Prognosis
(prog-NOH-sis)
The likely outcome or course of a disease; the chance of recovery or recurrence.
R
Radiation Therapy
(RAY-dee-AY-shun)
Also known as: Radiotherapy
The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors.
Remission
A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some but not all signs have disappeared. In complete remission, all signs have disappeared.
S
Stage
The extent of cancer in the body, including tumor size and whether it has spread. Staging helps determine the best treatment approach and prognosis.
Systemic Therapy
Treatment that travels through the bloodstream to reach cells throughout the body. Includes chemotherapy, hormone therapy, targeted therapy, and immunotherapy.
T
Targeted Therapy
A type of treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells.
TNM System
A system to describe the amount and spread of cancer: T describes tumor size, N describes spread to nearby lymph nodes, and M describes metastasis.
Tumor
An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer) or malignant (cancer).