Skip to the content

Cancer Terminology At A Glance


Absolute Neutrophil Count: The number of mature white blood cells that fight bacterial infections.

Acute: Having the abrupt onset of symptoms and a short course—not chronic.

Adenoma: A noncancerous tumor.

Adjuvant Chemotherapy: Chemotherapy given in coordination with radiation therapy and surgery.

Aggressive: A fast-growing cancer.

Alopecia: Hair loss that may include all body hair as well as scalp hair.

Angiogenesis: Blood vessel formation. Tumor angiogenesis is the growth of blood vessels from surrounding tissue to a solid tumor. This is caused by the release of chemicals by the tumor.

Antibody Therapy: Treatment with an antibody, a substance that can directly kill specific tumor cells or stimulate the immune system to kill tumor cells.

Aspiration: Removal of fluid from a cyst or cells from a lump, using a needle and a syringe.

Atypical Hyperplasia: Cells that are both abnormal (atypical) and increased in number.

Average Risk: A measure of the changes of getting cancer without the presence of any specific factors known to be associated with the disease.



Benign: Not cancerous—cannot invade neighboring tissues or spread to other parts of the body.

Biological Therapy: Treatment to stimulate or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Also known as immunotherapy, biotherapy, or biological response modifier (BRM) therapy.

Biomarkers: Substances sometimes found in an increased amount in the blood, other bodily fluids, or tissues and that may suggest the presence of some types of cancer.

Biopsy: The removal of a sample of tissue or cells for examination under a microscope for the purpose of diagnosis.

Brachytherapy: A procedure in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called internal radiation, implant radiation, or interstitial radiation therapy.



Cancer: A term for more than 100 diseases in which abnormal cells grow out of control; a malignant tumor.

Carcinoma: Cancer that begins in tissues, lining, or covering the surfaces (epithelial tissues) of organs, glands, or other body structures. Most cancers are carcinomas.

Carcinoma In Situ: Cancer that is confined to the cells where it began and has not spread into surrounding tissue.

Chemoprevention: The usage of drugs or vitamins to prevent cancer in people who have precancerous conditions or a high risk of cancer or to prevent the recurrence of cancer in people who have already been treated for it.

Chemotherapy: The treatment of cancer with drugs that can destroy cancer cells.

Chromosomes: Structures located in the nucleus of a cell, containing genes.

CBC: Complete blood count, showing your white blood cells (WBC), red blood cells (RBC), and platelet count.

CMP: Complete blood count, drawn at the beginning of each cycle. It shows kidney and liver function, as well as electrolytes.

Computed Tomography (CT) Scanning: An imaging technique that uses a computer to organize the information from multiple X-ray views and construct a cross-sectional image of areas inside the body.

Core Needle Biopsy: The use of a small cutting needle to remove a core of tissue for microscopic examination.

Cycle: One complete round/course of chemotherapy. Depending on your treatment plan, this might be one or multiple treatments. Each cycle begins with a visit to the physician.

Cyst: Fluid-filled sac.



Drug Resistance: Cancer cells that resist the effects of a specific chemotherapy drug.

Dysphagia: Difficulty swallowing.

Dyspnea: Difficult or painful breathing or shortness of breath.

Dysuria: Difficult or painful urination.



Edema: A localized or generalized condition in which the body tissue contains an excessive amount of tissue fluid.

Excisional Biopsy: The surgical removal (excision) of an abnormal area of tissue, usually along with a margin of healthy tissue, for microscopic examination.

External Beam Radiation Therapy: Radiation therapy that uses a machine outside of the body to deliver high-energy rays directed at the cancer or tumor.

Extravasation: When intravenous fluids or medications leak into tissue surrounding an infusion site. Extravasation may cause tissue damage.



False Negative: Test results that miss cancer when it is present.

False Positive: Test results that indicate cancer is present when the disease is truly absent.

Fine Needle Aspiration: The use of a slender needle to remove fluid from a cyst or cluster of cells from a solid lump.

Fistula: An abnormal opening between two body areas.

Frozen Section: A sliver of frozen biopsy tissue. A frozen section provides a quick preliminary diagnosis, but it’s not 100 percent reliable.



Genetic Change: An alteration in a segment of DNA, which can disturb a gene’s behavior and sometimes lead to disease.

Granulocyte: A white blood cell that kills bacteria.

Groshong: A thin-walled plastic tube that is tunneled under the skin near the heart to administer IV fluids, medications, or blood/blood products and/or withdraw blood for lab tests.



Hematocrit: The percentage of red blood cells in the blood. A low hematocrit indicates anemia.

Hematologist: A physician specializing in blood and bone marrow problems.

Hematology: The study of the blood.

Hematuria: Blood in the urine.

Hemoccult (guaiac test): A test that checks for hidden blood in the stool.

Higher Risk: A measure of changes of getting cancer when factor(s) known to be associated with the disease are present.

Hormones: Chemicals produced by various glands in the body, which produce specific effects on specific target organs and tissues.

Hospice: A program of supportive care to meet the special needs of patients, families, and/or support persons during terminal stages of illness. The care is delivered by a specially trained team of professionals in the home or hospital.

Human Leukocyte Antigen Test (HLA): A blood test that matches a blood or bone marrow donor to a recipient for transfusion or transplant.

Hyperplasia: Excessive growth of cells.



Immunotherapy: Boosting the body’s immune system with growth factors to treat or fight disease.

Incisional Biopsy: The surgical removal of a portion of an abnormal area of tissue, and cutting into (incising) it, for microscopic examination.

Infection: Invasion of body tissues by microorganisms such as bacteria and viruses.

Infiltrating Cancer: Cancer that has spread to nearby tissue, lymph nodes, or other parts of the body (same as Invasive Cancer).

Inflammation: The body’s protective response to injury (including infection). Inflammation is marked by heat, redness, swelling, pain, and loss of function.

Internal Radiation: A procedure in which radioactive materials sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called brachytherapy, interstitial radiation therapy, or implant radiation.

Interstitial Radiation: A procedure in which radioactive materials sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called brachytherapy, internal radiation therapy, or implant radiation.

Intracavitary Radiation: A radioactive source (implant) placed in a body cavity such as the cervix or esophagus.

Invasive Cancer: Cancer that has spread to nearby tissue, lymph nodes, or other parts of the body (same as Infiltrating Cancer).



Lumpectomy: Removal of the abnormal tissue in the breast and some of the tissue around it. It is usually followed by radiation therapy to the part of the breast that remains.

Lymphangiogram: A test to determine the size and shape of the lymph nodes.

Lymphatic System: The tissues of organs that produce, store, and transport cells that fight infection and disease.

Lymphedema: Inflammation either from obstructed cancerous lymph nodes or from surgically removed lymph nodes.

Lymphocytes: White blood cells that kill viruses and defend against the invasion of foreign material.



Magnetic Resonance Imaging (MRI): A technique that uses a powerful magnet linked to a computer to create detailed pictures of areas inside the body.

Malignancy: State of being cancerous. Malignant tumors can invade surrounding tissues and spread to other parts of the body.

Margin: The edge or border of the tissue removed in cancer surgery. The margin is described as negative or clean when the pathologist finds no cancer cells at the edge of the tissue, suggesting that all of the cancer has been removed. The margin is described as positive or involved when the pathologist finds cancer cells at the edge of the tissue, suggesting that not all of the cancer has been removed.

Medical Oncologist: A physician who specializes in diagnosing and treating cancer using chemotherapy, hormonal therapy, and biological therapy. A medical oncologist often serves as the main caretaker of someone who has cancer and coordinates treatment provided by other specialists.

Metastasize: To spread from the first cancer site to another part of the body. For example, breast cancer spreading to the bone.

Monoclonal Antibody: Laboratory-produced substances that can locate and bind to cancer cells whenever they are in the body. Many monoclonal antibodies are used in cancer detection or therapy; each one recognizes a different protein on certain cancer cells. Monoclonal antibodies can be used alone, or they can be used to deliver drugs, toxins, or radioactive material directly to a tumor.

Mutation: A change in the number, arrangement, or molecular sequence of a gene.



Needle Biopsy: Use of a needle to extract cells or bits of tissue for microscopic examination.

NADIR: This happens about 7–14 days after chemotherapy. Your blood counts dip to their lowest point. An office visit is schedules approximately 7 days after chemo to evaluate blood counts and other possible side effects from treatment.

Neoadjuvant Therapy: Treatment given as a first step to shrink a tumor before the main treatment, which is usually surgery, is given. Examples of neoadjuvant therapy include chemotherapy, radiation therapy, and hormone therapy. It is a type of induction therapy.

Neoplasm: Another word meaning cancer or benign tumor growth.

Neutropenia: When your WBC decreases causing increased risk for infection. GRAN/ANC: Slight increased risk = 1.0–1.4; Moderate risk = 0.5–1.0; High increased risk = fewer than 0.5.

NPO: This is a medical abbreviation that means “nothing by mouth.”



Occult Blood Test: This is a test to check if the stool contains blood.

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

Oncology Certified Nurse (OCN): A registered nurse who has met certain requirements

and successfully completed a certification exam in the field of cancer care.



Pain Scale: A method to measure the severity of pain.

Palliative Treatment: Treatment to relieve pain and disease symptoms not intended to cure the disease.

Palpation: Use of the fingers to press body surfaces, so as to feel tissues and organs underneath.

Pathological Fracture: A broken bone caused by cancer or some disease condition.

Pathologist: A physician who diagnoses disease by studying cells and tissues under a microscope.

PICC: Peripherally inserted central catheter, placed in the upper arm or chest. It has external lines that can be used to draw blood and administer medications. This requires daily flushing and weekly dressing changes. This device is designed for short-term use—usually two to six weeks.

Permanent Section: Biopsy tissue specifically prepared and mounted on slides so that it can be examined under a microscope by a pathologist.

Petechiae: Tiny areas of bleeding under the skin, usually due to a low platelet count.

Photons: High-energy rays that penetrate deep into the body.

Phytochemicals: Naturally occurring chemicals found in plants that may be important nutrients for reducing a person’s cancer risk.

Platelet: Blood cells responsible for clotting.

Ploidy: The amount of DNA that each tumor cell contains. Tumor cells that are diploid have a normal amount of DNA and tend to be less aggressive.

Polyp: A tissue growth protruding into a body cavity, such as a nasal or rectal polyp. Polyps may be benign or malignant.

P.O.: A medical abbreviation that means “taken by mouth.”

Port: An implanted device surgically placed. It is accessed with a special needle as needed to draw blood or administer medications. This device requires monthly flushing when not being used. It is designed for long-term use and may be removed after treatment.

Port-Film: An X-ray taken on the treatment machine to check that your treatment is accurate.

Positron Emission Tomography (PET) Scanning: A technique that uses signals emitted by radioactive tracers to construct images of the distribution of the tracers in the human body.

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

Prognosis: The estimation of the likely outcome of a disease or patient’s life expectancy.

Protocol: The cancer treatment plan.



RAD: A unit of measure for radiation. It stands for radiation absorbed dose.

Radiation: Energy carried by waves or by streams of particles. Various forms of radiation can be used in low doses to diagnose disease and in high doses to treat disease (see X-rays).

Radiation Oncologist: A physician who specializes in using radiation to treat a variety of diseases including cancer.

Radiation Physicist: A person who makes sure that the radiation machine or implant delivers the correct amount of radiation to the correct site on the body. The physicist works with the radiation oncologist to choose the treatment schedule and dose that has the best chance of killing the most cancer cells.

Radiologist: A physician with specific training in the use of diagnostic imaging—such as CT, MRI, PET, and ultrasound—to image body tissues and treat disease.

Recurrence: The reappearance of cancer after a period of remission.

Red Blood Cells (RBC): Blood cells that deliver oxygen to tissues and remove carbon dioxide from them.

Red Blood Count: The number of red blood cells in a blood sample.

Regression: The shrinkage of cancer growth.

Relapse: The reappearance of cancer.

Remission: Complete or partial disappearance of a cancer.

Risk: A measure of the likelihood of some uncertain or random event with negative consequences for human life or health.

Risk Factors (for cancer): Conditions or agents that increase a person’s chances of getting cancer. Risk factors do not necessarily cause cancer; rather, they are indicators, statistically associated with an increase in likelihood.

ROV: Routine office visit. This is an office visit scheduled when your next cycle of chemotherapy begins.



Simulation: Uses an X-ray machine to identify the cancer area to be treated.

Simulator: An X-ray machine used to plan radiation treatment.

Specimen X-Ray: An X-ray of tissue that has been surgically removed (surgical specimen).

Staging: A measure of the extent of cancer.

Surgical Biopsy: The surgical removal of tissue for microscopic examination and diagnosis. Surgical biopsies can be either excisional or incisional.

Surgical Oncologist: A physician who performs operations such as the removal of breast lumps or tumors.

Systemic Disease: A disease that affects the whole body instead of one organ.



Targeted Therapy: The treatment of cancer with drugs that target specific cancer cells. (Only in certain cancers.)

Teletherapy: The use of an X-ray machine to direct high energy at cancer.

Thrombocytopenia: A low number of platelets (thrombocytes). If there are too few platelets, bleeding may occur.

Treatment Field: The area on a patient’s body that will receive radiation.

Tumor: An abnormal growth of tissue. Tumors may be either benign or cancerous.

Tumor Markers: Proteins (either amounts or unique variants) made by altered genes in cancer cells that are involved in the progression of the disease.



Ultrasound: The use of sound waves to produce images of body tissues.

Unsealed Internal Radiation Therapy: Radiation therapy given by injecting a radioactive substance into the bloodstream or a body cavity, or by swallowing it. This substance is not sealed in a container.



Vesicant: Any intravenous medication that causes pain, swelling, or tissue damage if leaked into tissues.



White Blood Cells (WBC): A variety of cells that fight germs or infection. Specific white blood cells include granulocytes and lymphocytes.



X-Ray: A high-energy form of radiation. X-rays form an image of body structures by traveling through the body and striking a sheet of film.