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What the Medical Words Mean

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Adenoma: A non cancerous or pre cancerous tumor. An example is a polyp in the bowel.

Adenocarcinoma: Cancer that begins in the cells that line the internal organs and that have gland-like properties.

Adjuvant Therapy: Another treatment used with the primary treatment to decrease the risk of the cancer returning. For example, the primary treatment for breast cancer may be surgery, followed by the adjuvant treatment of chemotherapy.

Alopecia: The loss of hair from parts of the body where hair is normally found. It is often a side effect of cancer treatment.

Anemia: A condition in which the red blood cells are below normal. Signs of anemia include a pale color, tiredness,  shortness of breath, feeling cold and trouble concentrating or remembering.

Antibody: A protein made by cells of the immune system to counteract antigens.

Antigens: Foreign materials to the body like bacteria, viruses and toxins. They often are associated with allergic reactions. 


Basal Cell Cancer: Cancer that begins in the outer layer of the skin. It may appear as a small white or flesh colour bump that grows slowly and may bleed. This type of cancer is usually found on areas of the skin that are exposed to the sun like the face, ears and backs of hands.

Benign tumor: An abnormal collection of healthy looking cells. They usually do not spread to other parts of the body. They can be harmful if they get big enough to put pressure on organs, blood vessels or nerves.

Bilateral: Occurring on both sides of the body.

Biopsy: The removal of cells or tissues for examination under the microscope.

Bone Marrow: A soft substance found in bone cavities. It is composed of developing red cells, white cells , platelets cells and fats.

Bone metastasis: Cancer that has spread from the original tumor into the bone.

Brachytherapy: A type of radiation therapy in which radioactive material is placed into the body to be close to the tumor. The radioactive material is usually put into a wire, catheter, needle or pellet before it is inserted into the body. 


  A kind of cancer that starts in the skin or in the lining of organs. Lungs, intestines and the uterus are hollow organs where a carcinoma often begins.

Chemotherapy: The use of drugs to destroy cancer cells. A person on chemotherapy may take one drug or a combination of drugs.  Drugs are given through the vein using intravenous infusion. Some can be taken in the pill form or needle form.

Clinical trials: The goal of clinical trials is to find better treatments to fight cancer. These treatments may work better or be safer than current therapies, or both.

Colonoscopy:  A procedure to inspect the rectum and colon by means of a long fibre optic- telescope.The scope is passed through the rectum and into the colon allowing the doctor to see the inside of the bowel and to take a biopsy if necessary.

Colostomy: An artificial opening in the abdomen, created to drain feces from the colon into a bag.

Colposcopy: A procedure for detecting small lesions of the cervix by inspecting that part of the body with  a special binocular magnifying instrument.

Cryosurgery: The use of a special cold probe as a surgical instrument to destroy cancer cells.

Combination chemotherapy: Using more than one anticancer medication together, with the goal of destroying more cancer cells.

CBC (complete blood count): The CBC is a test that determines the number of red blood cells, white blood cells, and platelets in the blood.

Cycle: Chemotherapy can be given in a variety of time arrangements, such as daily, weekly, or monthly. Chemotherapy is generally given in cycles. A cycle can last 1 or more days but usually lasts 2, 3, or 4 weeks.

Cystitis: An inflammation and irritation of the bladder caused by bacterial infection, chemotherapy and/or radiation therapy. Symptoms include a burning sensation when urinating or an urgent, frequent need to urinate.

Cystoscopy:  a procedure that allows a doctor to inspect the inside of the bladder by means of a telescope. The telescope can also take a biopsy if necessary.


Debulking: A surgical procedure that attempts to remove  as much of the cancer as possible, where it is not possible to remove all the cancer.

Drug-resistance:  The ability of cancer cells to resist the effects of a specific drug.

Dysphagia:  Difficult or painful swallowing.

Dyspnea:  Difficult or painful breathing. Shortness of breath.

Dysuria:  Difficult or painful urination.


Edema: The build up of fluid within the tissues of the body. Swelling.

Effusion: A collection of fluid in a body cavity such as the lungs, heart or intestines. For example, a pleural effusion is the collection of fluid between the lung and pleura (the lung’s lining).

Electrocardiogram (EKG or EGG):  A test that makes recordings of the electrical impulses of the heart. Abnormal recordings may indicate forms of heart disease.

Emboli: A collection of cells that clump together in the bloodstream and block the flow of blood to certain parts of the body.

Emesis: Another word for vomiting.

Endoscopy:  A method of looking at the inside of body cavities, such as the esophagus (food pipe) or trachea (windpipe). The doctor is able to take photographs, obtain small samples of tissue or remove small growths during the procedure. The instrument used is an endoscope.

Erythema:  Redness of the skin.

Erythrocyte:  A red blood cell. It carries oxygen to body cells and carbon dioxide away from body cells.

Esophagitis:  An inflammatory response of the esophageal lining that may lead to infection, difficulty swallowing, bleeding or ulceration.

Estrogen:  A female hormone produced by the ovaries and adrenal glands.

Estrogen receptor assay (ER assay):  A test that determines whether breast cancer is stimulated by the hormone estrogen.

Excision:  Surgical removal of tissue from the body, including cancerous growths.

Extravasation:  The leaking of a vesicant drug or intravenous fluids or medications into tissue surrounding the infusion site. Extravasation during chemotherapy may cause tissue damage. 


Familial Polyposis: A hereditary condition in which members of the same family develop intestinal polyps which can lead to colon cancer.

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 white blood cell count (neutropenia). Having a fever during neutropenia is often a sign of infection.

Fine Needle Aspiration: The insertion of a small needle into a certain part of the body to take a small piece of tissue for testing.

Frozen Section: A procedure done by the pathologist during surgery to give the surgeon an immediate answer to whether a tissue is cancerous or not. 

Grade: The measurement of a cancer, reflecting how abnormal the cells look under a microscope.  A specialist called a pathologist performs the grading by examining the biopsy specimen.

Granulocyte:  A type of white blood cell that kills bacteria. 

Hematologist:  A doctor who specializes in problems of the blood and bone marrow.

Hematology:  The science that studies the blood.

Hematuria:  Blood in the urine.

Hepatic: Involving the liver.

Hgb (hemoglobin): The part of the red blood cell that carries oxygen from the lungs to other organs in the body, such as the brain and the heart. A person with a low hemoglobin level may have anemia.

Hormonal 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.

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

Immune system: The body's defense system against bacterial, viral and fungal infections. The immune system includes white blood cells and protective barriers such as the skin and mucous membranes. The principal organs of the immune system are the bone marrow, spleen and lymph system.

Infection: An invasion of microorganisms that have the ability to multiply and produce disease.

In situ:  A very early stage of cancer in which the tumor is isolated to only one area.

Invasive cancer: Cancer that has spread to the healthy tissue surrounding the original tumor. 

Laryngoscopy: A procedure of looking at the back of the throat, pharynx and larynx(voice box) with a special tube.

Lesion:  Any abnormal body tissue.

Leukocyte: A type of white blood cell that fights infection.

Leukopenia: A decrease in white blood cells.

Lobectomy:  The removal of one lobe of a lung. The right lung has 3 lobes and the left lung has 2 lobes.

Lumpectomy: The removal of a breast cancer lump and some of the healthy tissue surrounding the lump.

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.

Lymphedema: Swelling, usually of an arm or leg, caused by a blockage of the lymph nodes or lymph vessels. 


Malignant: Malignant means that a tissue has cancer cells in it that come from a different site in the body; it also refers to a cancerous disease.

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 on tests.

Myelosuppression: Myelosuppression occurs when the bone marrow slows production of blood cells. This results in fewer red blood cells, white blood cells, or platelets available to perform their normal functions in the body. Chemotherapy can cause decreased bone marrow function. Most often, myelosuppression refers to the loss of white blood cells.

Neoadjuvant chemotherapy: Chemotherapy given before surgery in order to shrink the tumor.

Nadir: The lowest point to which blood cells fall after cancer treatment.

Narcotic: The legal term describing pain relieving substances whose use is closely regulated by the government.

Nasopharynx: The part of the nasal cavity behind the nose and about the part of the throat that we can see.

Nausea: Feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

Needle biopsy: The procedure of  placing a needle into a lump  to obtain a small amount of the lump for examination under a microscope.

Neoplasm: A new abnormal growth that could be cancerous or noncancerous.

Nephrotoxic: A term generally used to advise about a drug’s ability to have toxic effects to the kidney.

Neuropathy: Malfunction of a nerve, often causing numbness or weakness.

Neurotoxicity: A term generally used to advise about a drug’s toxic effects to the nervous system.

Nasopharynx: The upper part of the throat behind the nose. An opening on each side of the nasopharynx leads into the ear. 

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

Oophrectomy: The surgical removal of one or both ovaries. 


Palliative treatment:  Treatment that relieves pain and symptoms of a disease but does not cure it.

Pap (Papanicolaou) smear:  A test to detect cancer of the cervix, done during a pelvic examination.

Paracentesis:  Removal of fluid from the abdomen using local anesthesia, a needle and syringe.

Pathological fracture:  A break in a bone usually caused by cancer or another disease condition.

Pathology:  The study of disease by examining tissues and body fluids. A doctor who specializes in pathology is called a pathologist.

Pathologist: The pathologist examines biopsy specimens and determines if cancer cells are present.

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

Phlebitis:  Painful swelling of a vein.

Photosensitivity:  Extreme sensitivity to the sun, which leaves a person prone to sunburn. Some antibiotics and cancer drugs cause this side effect.

Plasma:  The fluid portion of blood in which blood components are suspended.

Platelet (pIt):  Small cells in the blood that are responsible for clotting.

Platelet count:  The number of platelets in a blood sample.

Pneumonectomy:  Surgical removal of a lung or part of a lung.

Polyp:  An overgrowth of tissue protruding into a body cavity — for example, a nasal or rectal polyp. These are usually benign but are often surgically removed since they may become cancerous.

Poorly differentiated: A term used to describe the appearance of cancer cells. The cells only slightly resemble the healthy tissue surrounding it.

Port (infusion):  A quarter-sized disc that is surgically placed just below the skin of the chest or abdomen. A tube is inserted into the port so fluids, drugs or blood products can be infused through a needle directly into the bloodstream.

Primary tumor:  The original cancer, usually named after the area where it started. For example, breast cancer that has spread to the bone is still called breast cancer.

Prophylactic:  A term used to describe a treatment that prevents a disease or complication.

Progesterone:  One of the female hormones produced by the ovaries.

Progesterone-receptor assay:  A test that determines if breast cancer is stimulated by female hormones.

Prognosis:  The predicted outcome of a disease.

Prostate:  A gland located at the base of the bladder in males.

Prosthesis:  Artificial replacement of a missing body part, such as a leg, breast or eye.

Protocol:  A treatment plan that includes the drugs, dosages and dates of cancer therapy. 


Radiation therapy:  X-ray treatment that damages or kills cancer cells.

Radiologist:  A doctor and/or therapist who specializes in the use of x-rays to diagnose disease.

Radiosensitizer:  A drug or biologic agent that is given along with radiation treatment to increase its effects.

Recurrence:  Reappearance of a disease after treatment had caused it to disappear.

Red blood cells:  Small cells in the blood that carry oxygen to tissues and take carbon dioxide from them.

Red blood count (RBC):  The number of red blood cells in a blood sample.

Regression:  Shrinkage of a cancer tumor.

Relapse:  A return of cancer after it had been controlled by treatments.

Remission:  Complete or partial disappearance of a disease; the period when the disease is under control.

Resistance: A term used to describe the failure of a tumor to respond to cancer treatment. 

Sarcoma:  A malignant tumor of muscles or connective tissues such as bone and cartilage.

Side effects:  Unwanted or unintended reactions to drugs or radiation.

Small cell carcinoma:  See Carcinoma.

Sigmoidoscopy: See Colonoscopy

Sputum:  A mixture of saliva, mucus, cells and bacteria coughed up from the lungs or throat.

  Determining the distinct phase or period in the course of a disease.

Steroids:  A class of fat-soluble chemicals that are vital to many functions within the body. They are often used in cancer treatment.

Stilbesterol:  A female hormone, frequently given to prostate cancer patients.

Stomatitis:  Inflammation and soreness of the mouth, sometimes a side effect of chemotherapy.

Systemic disease:  A disease that affects the whole body instead of just one area. 

Taste alteration:  A change in taste perception that often causes foods to taste bland or unappealing.

Testicular self-examination (TSE):  A simple exam of the testicles that men should perform themselves to detect early stages of cancer or other problems.

Thoracentesis (pleural tap):  The removal of fluid from the area between the lung and its lining.

Thrombocytopenia:  An abnormally low number of platelets (thrombocytes) due to disease, reaction to a drug or toxic reaction to chemotherapy treatments. If there are too few platelets, bleeding can occur.

Tomography:  A test using computers or x-rays to see part of the body following injection of a dye.

Toxic reaction:  Serious side effects. Some are dangerous or poisonous.

Trachea:  The tube descending from the larynx and branching into the left and right bronchi.

Tracheostomy:  A surgical opening through the trachea in the neck to provide an artificial airway. This is performed when the trachea is blocked and the person cannot breathe.

Tumor:  An abnormal overgrowth of cells. Tumors are either benign or malignant.

Tumor marker:  Something that identifies or is used to identify a tumor.

TNM classification: A system of describing the stage of development for most types of cancers. T stands for tumor size N stands for lymph node involvement and M stands for the spread of the cancer to other parts of the body. 

Undifferentiated: A term used to describe the appearance of  tumor cells. They do not look like any of the healthy surrounding tissue. These cells tend to grow and spread quickly.

Ureter:  The tube that urine passes from the kidney to the bladder.

Urostomy:  A surgical procedure during which a new bladder is created outside the body. This is done by surgically culling the ureters from the bladder and connecting them to an opening outside the abdomen, thereby allowing urine to flow into a collection bag.

Uterus (womb):  The female organ that receives a fertilized egg and holds the fetus until birth. 


Venipuncture:  Puncturing a vein in order to obtain a blood sample, start an intravenous drip or give a medication.

Vesicant:  A substance that, if leaked into tissues, can cause swelling, tissue damage and destruction.

Virus:  A tiny infectious agent that is smaller than bacteria. The common cold is caused by a virus. 


Well-differenciated: A term used to describe the appearance of cancer cells. They look like the healthy cells around them.They tend to grow and spread a little more slowly than the undifferentiated cells.

White blood cells:  Cells responsible for fighting infection and allergy-causing agents.

White blood count (WBC):  The number of white blood cells in a blood sample.

Wilms’ tumour:  A malignant growth of the kidney that usually affects young children.
X-ray:  High energy electromagnetic radiation used to diagnose and treat disease.


Updated Feb 21, 2012