Colorectal Cancer Glossary of Terms








Adverse effect: a negative or harmful effect.

Analgesic: medicine to relieve pain.


Antibiotic: medication used to treat bacterial infections.








Aneurysm: the abnormal enlargement or bulging of a blood vessel, caused by damage or weakness in the blood vessel wall.

Angiogram/Angiography: a technique that uses dye to highlight blood vessels.

Anoscopy: an examination of the anus with a short, metal or plastic scope. The anoscopy procedure is used to look for hemorrhoids, anal polyps, or other causes of bright-red rectal bleeding.

Anus: the opening of the rectum positioned in the fold between the buttocks, situated at one end of the digestive tract where waste is expelled.

APC: (adenomatous polyposis coli) often referred to as a "tumor suppressor gene," APC is a gene that produces a protein to help slow down the rate at which cells divide and grow.

Asymptomatic: no symptoms; no clear evidence that disease is present.

Banding: a technique, used to study our genes, in which chromosomes are stained with fluorescent or chemical dyes to determine their characteristics.

Barium: a substance that, when swallowed or given rectally as an enema, makes the digestive tract visible on X-rays.

Barium enema: a process used to study the colon in which barium is given as an enema (through the rectum). Usually gas is then blown in to make the barium spread over the lining of the colon, producing an outline of the colon on X-ray to reveal any irregularities in the lining, such as a polyp, or growth.

Benign tumor: a non-cancerous growth that usually does not spread to nearby tissues or other parts of the body.

Biofeedback: a technique that gives a person some element of voluntary control over particular bodily functions. An electronic device that produces sight or sound signals is often used.

Biological therapy: see Immunotherapy.

Biopsy: the removal and examination of a sample of tissue with a microscope to see whether cancer cells are present.

Brachytherapy: a form of radiation therapy usually used to treat prostate and other cancers. During the procedure, radioactive seeds are implanted into the prostate gland. The seeds remain in place permanently and become inactive after about 10 months. This technique allows for delivery of a high dose of radiation to the prostate with limited damage to surrounding tissues.


Cancer: a general term for more than 100 diseases in which there is an uncontrolled, abnormal growth of cells. Cancer cells can spread to other parts of the body.


Carcinoma: a malignant (cancerous) growth that begins in the lining or covering of an organ and tends to invade surrounding tissue and travel to and grow in other regions of the body.

Carcinoma in situ: cancer that involves only the tissue in which it began; it has not spread to other tissues.

Catheter: a thin, flexible, plastic tube. A urinary catheter is a tube that is inserted into the bladder to drain urine.

CAT scan (CT Scan): a technique in which multiple X-rays of the body are taken from different angles in a very short period of time. A computer that displays a series of "slice" images of the body collects these images.

Chemotherapy: in cancer treatment, chemotherapy refers to the use of drugs whose main effect is either to kill or slow the growth of rapidly multiplying cells. Chemotherapy usually includes a combination of drugs, since this is more effective than a single drug.

Chronic: persisting over a long period of time.

Clear margins: an area of normal tissue that surrounds cancerous tissue, as seen during a microscopic examination. If margins are clear, the surgeon can be virtually sure that he or she has removed all the cancer in that area.


Colectomy, partial: a surgical procedure that involves removing part of the colon and joining the ends that remain. This is used to treat colon cancer or severe, chronic ulcerative colitis.

Colectomy, segmental: a surgical procedure that involves removing segments of the colon.

Colectomy, total: a surgical procedure that involves removing the entire colon, with the small intestine being attached to the rectum or a colostomy is attached.

Colitis: inflammation of the colon.

Colon: the last six feet of the intestine (except for the last eight inches, which is called the rectum); also called the "large intestine" or "large bowel."


Colon cancer: a malignant (cancerous) tumor arising from the inner wall of the large intestine. Although the exact causes of colon cancer are not known, it appears that both hereditary and environmental factors, such as diet, play a role in its development. The early stages of cancer may have no symptoms. Therefore, regular screening is important.

Colon and rectal surgeon: an expert in colon and rectal problems. Colon and rectal surgeons treat benign and malignant conditions, perform routine screening examinations, and surgically treat problems when necessary. They have completed advanced training in the treatment of colon and rectal problems in addition to full training in general surgery.

Colonoscopy: an outpatient procedure in which a doctor inserts a colonoscope (a long, flexible instrument about ½ inch in diameter) in the rectum and advances it to the colon to view the rectum and entire colon.

Colostomy: the surgical creation of an opening between the surface of the skin and the colon; also referred to as a large intestine stoma. This is usually done when very large areas of bowel are removed, and the ends cannot be joined, or when there is a blockage in the intestine.

Constipation: difficult, infrequent, or incomplete passage of stools. Constipation usually is caused by inadequate fiber in the diet or a disruption of regular routine or diet. Constipation can also be caused by overuse of laxatives, and can be a sign of a more serious medical condition. Constipation is also a side effect of narcotic analgesics.

Contraindication: a factor that makes use of a drug or other treatment inadvisable.

Crohn's disease: a chronic inflammatory disease that involves all layers of the intestinal wall. It primarily affects the lower part of the small intestine, called the ileum, but it can affect any part of the large or small intestine, stomach, or esophagus. Crohn's disease can disrupt the normal function of the bowel in a number of ways.

Desmoid tumors: growths of scar tissue that are very tough and firm. Desmoid tumors are rare among the general public, but are found in up to 13% of people with familial adenomatous polyposis, or FAP, who are at increased risk of colorectal cancer.


Diarrhea: a condition in which bowel movements are passed more often than usual and in a liquid state.

Digestive diseases: disorders that cause the malfunctioning of the digestive system, so that it is no longer turning food into fuel for energy, maintaining the body structure, or eliminating waste products properly. Digestive diseases range from the occasional upset stomach to colon cancer, and encompass disorders of the gastrointestinal tract, liver, gall bladder, and pancreas.

Digital rectal exam (DRE): a screening test used to detect tumors of the prostate and rectum.

Diverticulitis: an inflammation or infection of small sacs or outpouchings (diverticula) of the inner lining of the intestine that protrude through the intestinal wall.


DNA: the material that controls the genetics and heredity pertaining to each cell.

Double contrast barium enema: see Air contrast barium enema.

Duodenum: the first part of the small intestine, connecting with the lower opening of the stomach and extending to the jejunum.

Endoscopy: a method of physical examination using a lighted, flexible instrument that allows a physician to see the inside of the digestive tract. The endoscope can be passed through the mouth or through the anus, depending on which part of the digestive tract is being examined. This method is referred to by different names depending on the area of examination, such as: esophagoscopy (esophagus), gastroscopy (stomach), upper endoscopy (small intestine), sigmoidoscopy (lower third of the large intestine), and colonoscopy (entire large intestine).

Enema: injection of fluid into the rectum and colon to cause a bowel movement.

Epidural catheter: a small tube (catheter) passed into the space between the spinal cord and spinal column. Pain medication is then delivered through the tube.

Erythrocytes: red blood cells that carry oxygen from the lungs to cells in all parts of the body. Erythrocytes also carry carbon dioxide from the cells back to the lungs.

Esophagogastroduodenoscopy (EGD): an examination of the esophagus, stomach, and duodenum in which a thin flexible tube is placed down the throat. Before the EGD procedure, an anesthetic spray is used to numb the back of the throat, and sedation is given for the 15-minute exam.


Familial adenomatous polyposis (FAP): a syndrome in which a gene mutation that influences the development of colon, rectal, and other cancers is inherited. People with FAP usually have hundreds, and sometimes thousands of pre-cancerous polyps, or growths developing at a very early age. FAP is defined as the presence of more than 100 benign (adenomatous) polyps in the large intestine at one examination. Some people with FAP with a mild version of the disease have less than 100 adenomas; in these individuals the diagnosis is made by family history, or by finding the mutation during genetic testing. If untreated, cancers will develop in 100% of cases. Treatment is a total colectomy.

Fecal diversion: the surgical creation of an opening of part of the colon (colostomy) or small intestine (ileostomy) to the surface of the skin. The opening provides a passageway for stool to exit the body.

Fecal incontinence: also called accidental bowel leakage. The inability to retain stool, resulting in bowel accidents.

Fecal occult blood test: test used to detect blood in the stool. To screen for colon cancer, the test is recommended every year starting at age 50 if a colonoscopy is not used for screening. This test can be done in addition to the flexible sigmoidoscopy test every 5 years.

Fistula: an abnormal connection that forms between two internal organs or between two different parts of the intestine. This is a common complication of Crohn's disease.

Flexible sigmoidoscopy: a routine outpatient procedure in which the inside of the lower large intestine (called the sigmoid colon) is examined. Flexible sigmoidoscopies are commonly used to evaluate bowel disorders, rectal bleeding, or polyps (usually benign growths), and to screen people over age 50, with a barium enema for colon and rectal cancer. During the procedure, a physician uses a sigmoidoscope (a long, flexible instrument about 1/2 inch in diameter) to view the lining of the rectum and the large intestine. The sigmoidoscope is inserted through the rectum and advanced into the large intestine (colon) to view the lining of the rectum and the lower third of the large intestine (sigmoid colon).


Fluoroscopy: an X-ray technique that allows the doctor to observe how an organ performs its normal function; for example, how the esophagus works during swallowing.

Gas: a product of digestion that is made primarily of odorless vapors -- carbon dioxide, oxygen, nitrogen, hydrogen, and sometimes methane. The unpleasant odor is due to bacteria in the large intestine that release small amounts of gases containing sulfur. Everyone has gas and eliminates it by burping or passing it through the rectum. In many instances people think they have too much gas, when in reality they have normal amounts. Most people produce one to three pints of intestinal gas in 24 hours, and pass gas an average of 14 times a day.

Gastroenterologist: an expert in the treatment of diseases of the digestive (gastrointestinal) tract. They have completed advanced training in the treatment of digestive problems.

Gene: the basic unit of heredity found in all cells. Each gene occupies a certain location on a chromosome that contains the DNA that transfers genetic information.

Genetic counseling: a process in which a genetic counselor obtains a complete family and personal medical history in order to determine the probable existence of a genetic problem occurring within a family. The interpretation and implications of genetic testing are discussed. Often used for prospective parents in order to provide information about risks of diseases prior to conception, or during pregnancy. Genetic testing also helps inform those who are at risk of inheriting hereditary non-polyposis colorectal cancer and familial adenomatous polyposis (FAP), which increase the risk of getting colorectal cancer.

Genetic testing: blood or tissue tests that may be ordered to detect the presence of genetic abnormalities that place a person at risk for getting certain diseases, such as cancer. For patients and families suspected of having an inherited disease it may be possible to find the mutation causing the disease through genetic testing of blood.

Grade: a labeling system that is used to indicate a cancer's appearance as compared to normal tissue.

Hemorrhoids: swollen veins which line the anal opening, caused by excess pressure from straining during a bowel movement, persistent diarrhea, or pregnancy.


Hepatitis: a disease in which the liver is inflamed. A viral infection is usually the cause of hepatitis, although sometimes toxins or drugs are the cause.

Hereditary non-polyposis colorectal cancer (HNPCC): a syndrome in which a gene mutation influences the development of colon, rectal, and other cancers. Colon and rectal cancer occurs frequently in HNPCC families.


Hormones: chemicals produced by glands in the body. Hormones control the actions of certain cells or organs.

Ileal (J) Pouch: a pouch for holding stool that is used to replace the rectum after a total proctocolectomy. There are four forms of the ileal pouch, named after the shape in which the end of the small intestine (the ileum) is placed before it is sewn (or stapled) to make a pouch. The most common form is the "J" pouch, but there also are the "S," the "H" and the "W" pouches.

Ileocecal valve: The joining valve between the small and large intestines.

Ileocolectomy: surgical removal of a section of the terminal ileum and colon lying close to the ileum (the lowermost part of the small intestine).

Ileorectal anastomosis: the surgical connection of the ileum and the rectum.

Ileostomy: the surgical creation of an opening between the surface of the skin and the ileum, the lowermost section of the small intestine.

Ileum: the lower three fifths of the small intestine from the jejunum to the ileocecal valve.

Immune system: the body's natural defense system against infection or disease.

Immunotherapy: treatment to stimulate or restore the ability of the immune system to fight infection and disease; also called biological therapy.

Incontinence (bowel): loss of bowel control.

Inflammation: one of the body's defense mechanisms. Inflammation results in increased blood flow in response to infection and certain chronic conditions. Symptoms of inflammation include redness, swelling, pain, and heat.

Inflammatory bowel disease (IBD): diseases that cause inflammation of the bowel. IBD includes Crohn's disease and ulcerative colitis.


IV: see Intravenous.

Intravenous: medication given through a vein or veins using a small tube, or catheter.

Irritable bowel syndrome (IBS, also irritable bowel disease): a condition in which the colon muscle contracts more readily and causes abdominal pain and cramps, excess gas, bloating, and a change in bowel habits.

Jejunum: the second portion of the small intestine extending from the duodenum to the ileum.

Laparoscopy or laparoscopic surgery: a method of surgery that is much less invasive than traditional surgery. Tiny incisions are made to create a passageway for a special instrument called a laparoscope. This thin telescope-like instrument with a miniature video camera and light source is used to transmit images to a video monitor. The surgeon watches the video screen while performing the procedure with small instruments that pass through small tubes placed in the incisions.

Large intestine: the digestive organ made up of the ascending (right) colon, the transverse (across) colon, the descending (left) colon the sigmoid (end) colon and the rectum. The colon receives the liquid contents from the small intestine and absorbs the water and electrolytes from this liquid to form feces, or waste. Feces are then stored in the rectum until elimination from the body through the anus.

Laser surgery: destruction of tissue using a small, powerful, highly focused beam of light.

Laxative: medications that increase the action of the intestines or stimulate the addition of water to the stool to increase its bulk and ease its passage. Laxatives commonly are prescribed to treat constipation.

Local therapy: treatment that is directed at cells in the tumor and the area close to it.

Localized cancer: cancer that hasn't spread to other parts of the body.

Lymph: clear fluid that travels through the lymphatic system and carries cells that help fight infection and disease.


MRI: a test that produces images of the body without the use of X-rays. MRI uses a large magnet, radio waves, and a computer to produce these images.


Malignant: cancerous; can spread to other parts of the body.

Mesentery: membranous tissue that carries blood vessels and lymph glands, and attaches various organs to the inner wall of the abdomen.

Metastasize: to spread from one part of the body to another. When cancer cells metastasize and cause secondary tumors, the cells in the secondary tumor are like those in the original cancer.

Microsatellite instability: mistakes in DNA. Microsatellite instability is where the length of small sequences of DNA differs between tumor cells and normal cells; their appearance is a clue to the presence of abnormal DNA repair. The presence of microsatellite instability conveys resistance to fluoropyrimidine chemotherapy (5-FU or capecitabine).

Mismatch repair genes: genes responsible for correcting errors in DNA when cells divide. In hereditary non-polyposis colorectal cancer (HNPCC), recent research has discovered mutations in a variety of genes that are thought to be a part of the DNA mismatch repair system, therefore predisposing families with HNPCC to the development of cancer.

Mismatch repair: DNA constantly has to produce new strands of itself. When this is done incorrectly, there are special genes involved in correcting the mistake. If this is not done, or not done properly, a tumor can grow in the place of normal cells.

Muscle transposition: a procedure that borrows a working muscle to replace one that isn't working.

Mutation: a change in a gene with the potential of being transmitted to children.

Nausea: a queasy feeling that leads to stomach distress, a distaste for food, and an urge to vomit. Nausea is not a disease, but a symptom of many diseases. It can be brought on by illnesses such as influenza, medications, pain, and inner ear disease.

Nitrates: substances found in some foods, especially meats, prepared by drying, smoking, salting or pickling. Nitrates are thought to cause cancer.

Non-steroidal anti-inflammatory drugs (NSAIDs): drugs that reduce inflammation and pain that do not contain steroids. Examples of these drugs include aspirin, naproxen, and ibuprofen.

Occult blood: blood in the stool that is not visible to the naked eye. This type of bleeding is detected by performing a laboratory test on a stool sample.


Oncologist, medical: a doctor who specializes in the medical treatment of cancer. Medical oncologists have expert knowledge of how cancers behave and grow. This knowledge is used to calculate your risk of recurrence as well as the possible need for, and benefits of, additional or adjuvant therapy (such as chemotherapy, hormonal therapy or bone marrow transplantation). Your medical oncologist generally manages your overall medical care and monitors your general health during your course of treatment. He or she checks your progress frequently, reviews your lab and X-ray results and coordinates your medical care before and after your course of treatment.

Oncologist, radiation: a doctor trained in cancer treatment using radiation therapy.

Oncologist, surgical: a doctor who performs biopsies and other surgical procedures to diagnose and treat cancer.

Ostomy: a general term meaning an opening, especially one made by surgery; see also Colostomy.


Pathologist: an expert who specializes in analyzing tissue samples (removed during a biopsy) under a microscope to detect the cellular makeup of the tumor, whether the cancer is in just one place, whether it has the potential to spread, and how quickly it is growing. Pathologists can detect subtle differences in cancer cells that help your surgeon and oncologist confirm the diagnosis.

PCA: patient controlled analgesia, or PCA, is a method of administering pain medication that is activated by the patient.

Peristalsis: the means by which food or waste is propelled through the gastrointestinal tract in a series of muscular contractions.

Platelets: substance in blood that helps prevent bleeding by causing blood clots to form at the site of an injury.

Polyps (colon): small growths on the inner colon lining. Certain types of polyps, such as adenomas, may develop into cancer. Other types of polyps have no risk of developing into cancer. Colorectal screening is important to detect polyps and early cancer.

Proctocolectomy: the surgical removal of the entire colon and rectum.

Proctoscopy: a procedure in which a scope is used to examine the rectum.

Proctosigmoidectomy: an operation that removes a diseased section of the rectum and sigmoid colon.


Prognosis: the probable outcome or course of a disease; the chance of recovery.

Pulse oximetry: a device that measures the percent of oxygenation in the blood using a clip on the finger; also measures the heart rate.


Radiation, internal: when small amounts of radioactive materials are introduced into the body to help prevent, diagnose, and treat disease. Brachytherapy is the treatment of cancer with a radiation source that is applied in or near the tumor.

Radiation, external: the use of radiation delivered by special equipment that directs the radiation from outside the body through normal tissue to reach the cancer. This type of radiation to treat cancer often is given in short sessions over a period of time.

Radiation oncologist: a doctor who specializes in using radiation to treat cancer.

Radiation technologist: a professional who checks and delivers the radiation dosage to make it as safe as possible.

Radiology: a branch of medicine that uses various imaging techniques to diagnose and treat a wide variety of diseases.

Radiologist: a doctor who reads and interprets X-rays and other imaging techniques.

Rectal bleeding: a symptom of digestive problems rather than a disease. Bleeding can occur as a result of a number of different conditions, many of which are not life-threatening. Most causes of bleeding are related to conditions that can be cured or controlled, such as hemorrhoids. However, rectal bleeding may be an early sign of rectal cancer so it is important to locate the source of the bleeding.

Rectal prolapse: dropping down of the rectum outside the anus.

Rectopexy: surgical placement of internal sutures (stitches) to secure the rectum in its proper position.

Rectum: an 8-inch chamber connected to the large intestine that receives solid waste (feces) from the descending colon to be expelled from the body. The rectum connects the colon to the anus. It is the rectum's job to receive stool from the colon, to let the person know that there is stool to be evacuated, and to hold the stool until evacuation happens.


Recurrence: the return of a disease after a period of remission.

Remission: the disappearance of any signs and symptoms of cancer. A remission can be temporary or permanent.

Risk factor: a factor that increases a person's chance of developing a disease or predisposes a person to a certain condition.

Sentinel lymph node: the first lymph node to which a tumor drains, making it the first place where cancer is likely to spread.

Sigmoidoscopy: see Flexible sigmoidoscopy.

Small intestine: the portion of the digestive tract that first receives food from the stomach. It is divided into three sections: the duodenum, the jejunum, and the ileum. As food travels through the small intestine it is further broken down by enzymes, and nutrients from the food are absorbed into the bloodstream.

Sphincteroplasty: procedure performed to repair the anal sphincter.

Stage: a scoring system used to describe the extent of the cancer. The stage of colon cancer depends on the penetration of the tumor into and through the walls of colon and whether it has spread from its original site to other parts of the body.

Stoma: an artificial opening of the intestine to outside the abdominal wall.

Systemic therapy: treatment that reaches and affects cells all over the body.

Thrombosis: a blood clot in a blood vessel.

Total abdominal colectomy: surgical removal of the entire colon.

Trocar: a sharp, pointed instrument used to make a puncture incision in the abdominal wall; used for placement of cannulas (tubes that hold a laparoscope and other instruments in place during laparoscopic surgery).

Tumor: a spontaneous new growth of tissue forming an abnormal mass.

Ulcerative colitis: a disease that causes inflammation and sores, called ulcers, in the superficial layers of the lining of the large intestine. The inflammation usually occurs in the rectum and lower part of the colon, but it may affect the entire colon. Ulcerative colitis rarely affects the small intestine except for the lower section, called the ileum.



Vomiting : the forcible expulsion of the contents of the stomach through the mouth, which occurs with symptoms of nausea. Vomiting is not a disease but a symptom of many disorders. Vomiting is also a side effect of some forms of chemotherapy.

X-ray: high-energy radiation used in low doses to diagnose diseases and used in high doses to treat cancer.

WebMD Medical Reference Reviewed by Minesh Khatri, MD on February 05, 2018



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