Abdomen
The part of the body that contains organs including the pancreas, stomach, intestines, liver and gallbladder.

Anus
The excretory opening of the digestive tract from which waste is passed through the rectum out of the body.

Barium enema
A procedure in which a liquid with barium in it is distributed in the rectum and colon by way of the anus. Barium is a silver-white metallic compound that helps to show the image of the lower gastrointestinal tract on an X-ray.

Benign
Not cancerous; does not invade nearby tissue or spread to other parts of the body.

Biopsy
The removal of cells or tissues for examination under a microscope. When only a sample of tissue is removed, the procedure is called an incisional biopsy or core biopsy. When an entire tumor or lesion is removed, the procedure is called an excisional biopsy. When a sample of tissue or fluid is removed with a needle, the procedure is called a needle biopsy or fine-needle aspiration.

Bowel
Another name for the intestine, part of the digestive tract below the stomach.

Cancer
A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body.

Chemotherapy
Treatment with anticancer drugs.

Clinical trial
A research study that tests how well new medical treatments or other interventions work in people. Each study is designed to test new methods of screening, prevention, diagnosis or treatment of a disease.

Colon
The long, coiled, tube-like organ-also called the large bowel or large intestine-that removes water from digested food. The remaining material, solid waste called stool, moves through the colon to the rectum and leaves the body through the anus. The colon has four sections: the ascending colon, the transverse colon, the descending colon and the sigmoid colon.

Colonoscope
A thin, lighted tube used to examine the inside of the colon.

Colonoscopy
An examination of the inside of the entire colon using a thin, lighted tube (called a colonoscope) inserted into the rectum. If abnormal areas are seen, tissue can be removed and examined under a microscope to determine whether disease is present.

Colorectal
Having to do with the colon or the rectum.

Colostomy
An opening into the colon from the outside of the body. A colostomy provides a new path for waste material to leave the body after part of the colon has been removed.

Crohn's disease
One of the two most common types of inflammatory bowel disease, often diagnosed by X-ray or colonoscopy, that primarily involves the lower part of the small intestine but can occur anywhere in the intestinal tract. The condition, which can be caused by genetic factors, is usually diagnosed in people in their teens or twenties. In contrast to ulcerative colitis-which only affects the colon's inner lining-Crohn's disease inflames the entire thickness of the bowel wall. Common symptoms include abdominal pain, diarrhea, vomiting, fever and weight loss. People with the disease have a higher risk of developing colorectal cancer.

Digital rectal examination (DRE)
An examination in which a doctor inserts a lubricated, gloved finger into the rectum to feel for abnormalities.
 
Fecal occult blood test
A test to check for blood in stool, which can be a sign of colorectal cancer. (Fecal refers to stool; occult means hidden.)

Gastrointestinal (GI)
Relating to the digestive tract, which processes food to create energy and rid the body of waste. After food is partially digested in the stomach, it is sent to the small intestine, the longest section of the GI tract, and then to the large intestine. The digested waste moves from the colon into the rectum and passes out of the body in a bowel movement.

Intestine
The long, tube-like organ in the abdomen that completes the process of digestion; the intestine is comprised of the small intestine and the large intestine, which consists of the colon and rectum.
 
Lymph node
A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Also known as a lymph gland. Lymph nodes are spread out along lymphatic vessels and contain many lymphocytes, which filter the lymphatic fluid (lymph).

Malignant
Cancerous; a growth with a tendency to invade and destroy nearby tissue and spread to other parts of the body.
 
Medical oncologist
A doctor 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.
 
Metastasis
The spread of cancer from one part of the body to another. Tumors formed from cells that have spread are called "secondary tumors" and contain cells that are like those in the original (primary) tumor. The plural is metastases.

Polyp
A grape-like growth that protrudes from a mucous membrane. Precancerous polyps in the colon can be removed during a colonoscopy to prevent them from developing into colon cancer.
 
Polypectomy
Removal of a polyp during a colonoscopy or sigmoidoscopy.

Radiation oncologist
A doctor who specializes in using radiation to treat cancer.
 
Radiation therapy
The use of high-energy radiation from X-rays, gamma rays, neutrons and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body in the area near cancer cells (internal radiation therapy, implant radiation or brachytherapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that circulates throughout the body. Also called radiotherapy.

Rectum
The last 6 to 8 inches of the large intestine which stores solid waste from the colon until it leaves the body through the anus.
 
Risk factor
A habit, trait, condition or genetic alteration that increases a person's chance of developing a disease.

Screening
Conducting examinations or tests to detect diseases before symptoms are present. Screening allows for detection of diseases in their early, most treatable stages. In the case of colon cancer, the removal of precancerous polyps found during screening can actually prevent disease.

Sigmoidoscope
A thin, lighted tube used to view the inside of the colon.

Sigmoidoscopy
Inspection of the lower colon using a thin, lighted tube called a sigmoidoscope. Samples of tissue or cells may be collected for examination under a microscope. Also called proctosigmoidoscopy.

Stage
A number representing the degree to which a cancer has spread, including whether the disease has metastasized from the original site to other parts of the body
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Staging
Performing exams and tests to learn the extent of the cancer within the body, especially whether the disease has spread from the original site to other parts of the body.

Stool
Bodily waste excreted from the bowels.

Tumor
An abnormal mass of tissue that results from excessive cell division. Tumors perform no useful body function. They may be benign (not cancerous) or malignant (cancerous).

Ulcerative colitis
One of the two most common forms of inflammatory bowel disease in which chronic inflammation of the colon's inner lining produces ulcers. People with this condition-who often have abdominal pain, cramps and loose discharges of pus, blood and mucus from the bowel-are at higher risk of developing colorectal cancer.

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

This glossary is based on the National Cancer Institute's dictionary for cancer of the colon and rectum.