Your doctors and nurses may use many new and unfamiliar terms when they talk with you about your diagnosis, treatment, and recovery. When someone from your healthcare team uses a term that you don't understand, ask for a definition.

In addition, this section defines many terms and tests commonly used in discussing cancer care.

Acetaminophen—An analgesic medication that is used to reduce pain and fever (but not inflammation).

ANC (absolute neutrophil count)—ANC refers to the percentage of the total white blood cell count that is made up of cells called neutrophils. Neutrophils are particularly important because they defend our bodies against infection.

AML (acute myeloid leukemia)— AML is cancer of the bone marrow, which produces white blood cells that cannot carry out normal function. Signs of the disease include bleeding gums, fatigue, fever, bone pain, and repeated infections.

Adenocarcinoma—Cancer that begins in cells that line certain internal organs and that have gland-like (secretory) properties.

Adjuvant chemotherapy—Adjuvant chemotherapy is chemotherapy given after surgery, radiation, or other therapies to reduce the risk of cancer coming back.

Allogeneic bone marrow transplant— An infusion of bone marrow or stem cells from a donor who is genetically similar.

Alopecia—Alopecia is hair loss. Chemotherapy and sometimes radiation may make patients lose some or all of their hair during treatments. The most common area involved is the head, although other body hair can also be affected.

Analgesic—A medication that is used to relieve pain.

Anemia—Anemia is a lower-than-normal number of red cells in the blood. Red blood cells are important because they carry oxygen from the lungs to all other cells in the body. Shortness of breath, fatigue, and weakness are common signs of anemia.

Angiogenesis—The formation of new blood vessels. Tumor angiogenesis is the growth of new blood vessels that tumors need to grow.

Antibiotic—An antibiotic is a medication used to fight germs or bacteria that cause infection. Some chemotherapy can put patients more at risk for infection. Antibiotics are given to treat an infection.

Antiemetic—An antiemetic is a medication used to stop or help prevent nausea and vomiting, common side effects of some chemotherapy.

Autologous bone marrow transplant—During an autologous bone marrow transplant, a patient's own bone marrow is removed and then given back after intensive treatment such as high-dose chemotherapy.

Benign—Not cancerous. Benign tumors may also be referred to as nonmalignant.

Biopsy—Removal of a tissue sample from the body to see if the cells are cancerous. A doctor examines the cells under a microscope, comparing them to normal cells. Techniques to remove cells include:

  • Fine needle aspiration (FNA) biopsies use a thin needle attached to a syringe to withdraw a small amount of tissue from a tumor. When a slightly larger needle is used to remove a piece of tissue, it is called a core needle biopsy. Sometimes doctors use an ultrasound or a computed axial tomography, or CT, scan to view the tumor and assist them with needle placement.
  • During an excisional biopsy, a surgeon removes all visible tumor. During an incisional biopsy, only a small amount of tumor is removed. Both of these procedures involve a surgeon cutting through the skin. Sometimes the surgery requires general anesthesia, and sometimes it can be done by simply numbing the area to be cut (local anesthesia).

Blood cell count—a test that determines the number of red blood cells, white blood cells, and platelets in a blood sample.

Bone marrow transplant—A type of hematopoietic stem cell transplantation performed using stem cells collected from bone marrow.

Brachytherapy—Brachytherapy is radiation treatment inside the body. It uses radioactive materials placed close to the tumor to kill cancer cells while minimizing damage to normal tissues.

Bronchi—The large air passages that lead from the trachea (windpipe) to the lungs.

Cancer—A group of diseases where normal cells change into abnormal cells that grow out of control, invade surrounding tissues and organs, and may spread to distant sites in the body (metastases).

Carcinogen—A carcinogen is anything that may be linked to the development of cancer. Exposure to carcinogens can be due to lifestyle (eg, cigarette smoke), natural exposures (eg, UV light, radon gas), or other factors.

Carcinoma—Cancer that begins in the skin or in tissues lining or covering internal organs.

Central nervous system (CNS)—The brain and spinal cord.

Chemotherapy—The use of drugs to destroy cancer cells. A person on chemotherapy may take one drug or a combination of drugs. Most often these drugs are given by vein using intravenous infusion. Some can be taken by mouth or given in a shot.

Chemo side effects—A change in a person's condition caused by taking a drug, using a medical device, or through another type of treatment.

Cognitive deficits—Problems with thinking, learning, and memory; a side effect of some types of chemotherapy.

Combination chemotherapy—Using more than one anticancer medication together.

Complete blood count (CBC)—The CBC is a test that determines the number of red blood cells, white blood cells, and platelets in the blood. It is also called blood cell count.

Complete remission—Complete remission is when the cancer can no longer be detected, and all signs of cancer are gone. Partial remission is where some cancer does not completely disappear.

Constipation—Constipation is difficulty passing stool. It can also refer to a decrease in the normal frequency of bowel movements. It may be accompanied by gas, pain, or pressure in the abdomen.

Cryotherapy—A treatment method that uses cold temperature.

CT/CAT (computed axial tomography) scan—CT/CAT scans use x-rays taken from different angles to see internal organs. CAT scans are usually done in an outpatient clinic.

Cycle—The period of time when your receive chemotherapy plus the following period of rest. For example, one week of chemo plus 3 weeks of rest would make up one cycle of chemo.

Dehydration—A condition caused by the loss of too much water from the body. Causes include severe diarrhea or vomiting.

Diagnosis—Identification of a condition or disease based on the signs and symptoms.

Diarrhea—Bowel movements that occur more frequently and are more liquid in consistency than normal. Chemotherapy, medication, radiation, and infection may cause diarrhea. Diarrhea can also be caused by medications given to prevent nausea or by antibiotics given to treat or prevent infection.

DNA (deoxyribonucleic acid)—The molecules inside cells that carry genetic information and pass it from one generation to the next.

Dose intensity—The total amount of chemotherapy given during a specified period of time.

Ducts—A tube or vessel of the body through which fluids pass.

Electrolyte imbalance—Having too many or too few electrolytes in your body. That can happen when the amount of water in your body changes. Certain medications, vomiting, or diarrhea can cause an imbalance in the amount of water in your body.

Electrolytes— A substance that breaks up into ions (particles with electrical charges) when it is dissolved in water or body fluids. Sodium, potassium, and calcium are some examples of electrolytes. Electrolytes help the body work properly.

Endometrial cancer—Cancer that forms in the tissue lining the uterus (the small, hollow, pear-shaped organ in a woman's pelvis in which a fetus develops). Most endometrial cancers are adenocarcinomas (cancers that begin in cells that make and release mucus and other fluids).

Epithelial tumors—Cancer that begins in the cells that line an organ.

Erectile dysfunction—Inability to have an erection of the penis; also called impotence.

Extensive stage—Cancer cells have spread from the tissue of origin to other parts of the body. See limited stage.

External beam radiation—Radiation therapy in which radiation is directed from a source outside the body.

Fatigue—Fatigue means feeling tired, weak, sleepy, forgetful, or worn out, and having no energy to go about your daily routine. Fatigue is commonly caused by cancer treatments, but can also result from the disease itself. Fatigue is also often present in patients with anemia.

Febrile neutropenia—Having a fever and a low number of certain type of infection-fighting white blood cells called neutrophils. Having a fever during neutropenia may be a sign of infection.

Gastrointestinal (GI) tract—The stomach and intestines make up the gastrointestinal tract. The mouth, esophagus, liver, pancreas, gallbladder, rectum, and GI tract make up the digestive system.

Gene—A piece of DNA that contains information about hereditary characteristics such as hair color, eye color, and height, as well as whether one is at higher risk for developing certain diseases.

Grade—Grade is the measurement of a cancer, reflecting how abnormal the cells look under a microscope. There are several grading systems for cancer, but grades are commonly divided into 4 grades:

  • Least abnormality (grade 1 or well differentiated)
  • Intermediate features (grade 2 or moderately differentiated)
  • Greatest abnormality (grade 3 or 4 or poorly differentiated)

A specialist called a pathologist performs the grading by examining the biopsy specimen. Knowing the grade is important. A cancer's nuclear grade is based on features of the central part of its cells, the nucleus. The histologic grade refers to how much the tumor cells resemble normal cells of the same type of tissue.

Growth factors—A substance that is normally produced in the body that is involved in cell division, maturation, or survival. Growth factors may also be produced in a laboratory to mimic the growth factors naturally produced by the body. These synthetic growth factors may be used as biologic therapy to stimulate the immune system.

Hemoglobin (Hb)— The part of the red blood cell that carries oxygen from the lungs to other organs in the body.

Hematocrit (Hct)— The percentage of blood that is made up of red blood cells.

Hematopoietic stem cell transplant—Procedure that replenishes the supply of normal stem cells that are destroyed by high-dose chemotherapy and/or radiation therapy as part of a patient's cancer treatment; also called stem cell transplantation (SCT).

Hematopoietic stem cell—Specialized cell in the bone marrow that produces white and red blood cells and platelets.

HER2 (human epidermal growth factor receptor 2)—A protein involved in cell growth. It can be found in breast, ovarian, and other types of cancer cells.

Hormone—A chemical made by glands in the body that circulate throughout the bloodstream and control the actions of certain cells and organs.

Hormone therapy—A type of cancer treatment that affects hormones in the body, such as drugs that block hormone production or change the way hormones work.

Hyperfractionated radiation—A radiation treatment in which a dose of radiation is divided into smaller doses to be given over the course of a day.

Hypokalemia—Low potassium levels in the blood.

Hyponatremia—An imbalance between sodium and water in the body (too little sodium to water).

Immune system—The body's defense system against infections. The immune system includes white blood cells such as neutrophils and lymphocytes and protective barriers such as the skin and mucous membranes.

Immunotherapy—A type of therapy that stimulates the immune system to help fight cancer. Immunotherapy may also be used to lessen side effects of treatment. Immunotherapy is sometimes referred to as biological therapy.

Infection—An invasion of microorganisms (bacteria, viruses, fungi, and parasites) that have the ability to multiply and produce disease.

Infertility—The inability to have children.

Inflammation—Redness, swelling, pain, and/or a feeling of heat in an area of the body, often due to infection, irritation, or injury.

Infusion—A process of delivering medications, fluids, or blood products into the bloodstream through a vein.

Intensity-modulated radiation treatment—A radiation therapy technique that delivers thin beams of radiation directly to a tumor but reduces damage to normal tissue nearby.

Internal radiation—Radiation therapy in which a radioactive source is placed inside the body near the cancer site.

Intra-arterial—Within an artery.

Intraperitoneal (IP)—Within the area that contains the abdominal organs (peritoneal cavity).

Intravenous (IV)— Into a vein. An intravenous medication is delivered into the body through a vein.

Jaundice—A yellowing of the skin caused by elevated levels of bilirubin.

Leukemia—Cancer that begins in the cells of blood-forming tissue (eg, bone marrow).

Limited stage—Limited stage cancer is found only in the site of origin. See extensive stage.

Lobules—A small lobe (part of an organ, such as in the lung, brain, or thyroid) or a subdivision of a lobe.

Local therapy—Cancer treatment that only affects a tumor and the area close to it.

Lymph nodes—Lymph nodes are small, oval glands found throughout the body. They act as filters and fight infection. Cancer cells often spread to other parts of the body through the lymphatic system.

Lymphoma—Cancer that begins in cells of the immune system.

Malignant—Cancerous. Malignant cells can spread to other parts of the body.

Malnutrition—A condition caused by not getting enough calories or nutrients such as vitamins and minerals. Causes of malnutrition include not getting enough nutrients in your diet or not being able to absorb nutrients, both of which can result from cancer or some cancer treatments.

Menopause—The time of life when a woman's ovaries stop producing hormones and menstrual periods stop; usually occurs naturally around age 50.

Metastasis—The spread of cancer from one part of the body to another.

Micrometastases—Small amounts of cancer cells that have spread throughout the body but are too few to be detected in a screening or diagnostic test.

Modality—A method of treatment. A multi-modality treatment regimen involves several types of treatment, such as chemotherapy, radiation, and surgery.

Monoclonal antibody—Targeted cancer treatment that involves a type of protein, made in a lab, that can bind to substances in the body, including tumor cells. Each monoclonal antibody is made to target a specific substance.

Mouth sores— Inflammation or irritation of the mouth. Also called stomatitis. Certain kinds of chemotherapy can cause mouth sores.

MRI (magnetic resonance imaging)—A imaging procedure using radio waves and a powerful magnet to create detailed pictures of areas inside the body.

Mucositis—Inflammation of the lining of the digestive tract, often caused by cancer treatment. Sores can often occur in the mouth. See stomatitis.

Myelosuppression—Myelosuppression occurs when the one marrow slows production of blood cells. This results in fewer red blood cells, white blood cells, and/or platelets.

Nausea—Feeling queasy or sick to your stomach.

Neoadjuvant chemotherapy—Chemotherapy given to shrink a tumor before surgery or another type of treatment happens.

Neutropenia—A lower-than-normal number of neutrophils (infection-fighting white blood cells) in the blood.

Neutrophil—A type of white blood cell that helps the body fight infection. Since the most common type of white blood cell is the neutrophil, a low white blood cell count usually indicates that the neutrophil count is low. It is easier to get an infection and harder to recover from an infection when the number of neutrophils in the bloodstream is low.

NSAID (nonsteroidal anti-inflammatory drug)—A drug that decreases inflammation, fever, and pain.

Oncology nurse—A health professional trained to care for people who have cancer. A key member of the care team for a person going through chemo.

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

Opioid—A substance used to treat moderate to severe pain that binds to opioid receptors in the central nervous system.

Oral—The mouth. Medication given orally is given by mouth (eg, tablet or liquid).

Palliation—Relief of symptoms and suffering caused by cancer and other life-threatening diseases. Palliation helps a patient feel more comfortable and may improve quality of life, but does not cure the disease.

Palliative care—Palliative care focuses on controlling symptoms and improving quality of life for patients who have incurable diseases.

Partial remission—Partial remission is a significant decrease in the number of cancer cells but not their complete disappearance in response to the cancer therapy.

Pathologist—A doctor who studies cells and tissues to identify diseases.

Peripheral neuropathy—A side effect of some chemotherapy, characterized by numbness, tingling, or burning in the hands and feet.

Peripheral stem cell transplant—Process by which stem cells are removed from the blood of a patient or donor and are processed and stored. After chemotherapy or radiation, the stem cells are infused back into the patient. The stem cells find their way back to the patient's bone marrow and begin making healthy blood cells.

Peristalsis—The contraction and relaxation movements in the intestines and other tubular organs that move the contents forward.

Platelets—A cell fragment found in the blood. The main function of platelets is to aid in clotting the blood following an injury. Chemotherapy can cause the platelet count to drop, creating a risk of bleeding.

Prognosis—A prediction of the likely outcome of a disease based on the current health of the patient and the usual course of the disease.

Proliferating—Increasing in number. Cells proliferate by dividing.

Radiation therapy—A cancer treatment that uses the radiation from x-rays, gamma rays, protons, and other sources to kill cancer cells. Radiation therapy can be used alone or in combination with surgery and chemotherapy.

Red blood cell—Red blood cells are made in the bone marrow and released into the blood. They circulate in the blood and carry oxygen to all parts of the body. Too few red blood cells can lead to anemia.

Regimen—A plan of treatment, including doses, scheduling, and duration of treatment.

Relapse—The return of a disease after a period of improvement.

Remission—The disappearance of a cancer. Complete remission is the disappearance of all signs of cancer after treatment. Partial remission is a notable decrease in cancer cells, but not their complete disappearance.

Risk factor—Anything that increases the risk of developing a disease. Some risk factors such as smoking can be controlled. Other risk factors such as age and family history cannot be controlled.

Sarcoma—Malignant cancer of the bone, muscle, fat, cartilage, blood vessels, or other connective or supportive tissue.

Serotonin —A chemical found in the intestines, central nervous system, and other tissues. Chemotherapy causes serotonin and other chemicals to be released, triggering the nausea and vomiting reflex.

Side effect—A change in a person's condition caused by taking a drug, using a medical device, or through another type of treatment.

Squamous cell carcinoma—Cancer that begins in squamous cells. These thin, flat cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Squamous cell carcinoma is also called epidermoid carcinoma.

Stage—The extent or severity of a cancer. The stage is determined after performing tests, which may include physical exams, lab tests, x-rays, CT/CAT scans, and sometimes surgery. Some of the important factors for determining stage are the size of a tumor, whether lymph nodes contain cancer, and whether the disease has spread.

Stage II breast cancer—Breast cancer is considered stage II when the tumor can be described as being: a) no more than 2 centimeters wide and has spread to lymph nodes under the arm; b) between 2 and 5 centimeters across and may or may not have spread to lymph nodes under the arm; c) larger than 5 centimeters but has not spread to lymph nodes under the arm.

Stem cell transplantation—A procedure for replacing cells that form the blood, which typically reside in the bone marrow. Stem cells are infused into a patient to make healthy blood cells. A transplant can be done with a patient's own stem cells or with cells donated by someone else.

Sterility—The inability to produce children.

Stomatitis—Inflammation or irritation of the mouth. Certain kinds of chemotherapy can cause stomatitis.

Stool impaction—A large, dry mass of feces that can develop in the rectum. Chronic constipation can cause stool impaction. The stool can become so hard that it cannot come out of the body. Watery stool may seep past the dry stool, causing diarrhea.

Stromal cells—A cell that makes up certain types of the supporting tissue which surrounds organs and other tissues.

Symptom—A sign or indicator of a disease or illness. For example, a fever can be a symptom of an infection.

Systemic therapy— Cancer treatment that affects cells throughout the body. Chemotherapy is a systemic treatment.

Targeted therapy—A type of therapy using drugs to attack specific cells.

Thrombocytes— A cell fragment found in the blood. Thrombocytes are also called platelets. Their main function is to aid in clotting the blood following an injury. Chemotherapy can cause the thrombocyte count to drop, creating a risk of bleeding.

Thrombocytopenia—A condition in which there is an abnormally low number of platelets (thrombocytes) circulating in the blood. Excessive bleeding may occur if the platelet count is very low.

Transfusion—An intravenous infusion of blood or parts of blood.

Tumor—A mass of tissue made up of abnormal cells. Tumors can be malignant (cancer) or benign (not cancer).

Tumor markers—Substances found in tumor tissue or in the blood or other body fluids that are associated with particular kinds of cancer. These chemicals can be measured to help doctors diagnose cancer and evaluate the effectiveness of a cancer treatment. A rise in the level of a marker could mean the cancer is growing; a drop in the level could indicate the treatment regimen is effective.

Ulceration—A break on the skin or on the surface of an organ. Ulcers are sometimes associated with cancer.

Uterine sarcoma—Cancer that forms in the tissues of the uterus. It is a rare uterine cancer. The two main types are leiomyosarcoma and endometrial stromal sarcoma.

VAD (vascular access device)—VADs are catheters, or "ports", that are surgically placed in a large vein near the heart and stay in place for long periods of time. When a VAD is used, smaller, more easily irritated veins in the arms do not have to be accessed for chemotherapy.

White blood cell—A type of immune cell. White blood cells are responsible for fighting infection. There are several kinds of white blood cells, including monocytes, lymphocytes, neutrophils, eosinophils, and basophils.

X-ray—A type of radiation, x-rays are used in low doses to diagnose and assess cancer. During an x-ray, a small amount of radiation passes through the body and leaves an image of the shape of the internal organs on film. At higher doses, x-rays are used to treat cancer.

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