Colorectal Cancer

About Colorectal Cancer

Colorectal cancer is malignant cells found in the colon or rectum. The colon and the rectum are part of the large intestine, which is part of the digestive system. Because colon cancer and rectal cancers have many features in common, they are sometimes referred to together as colorectal cancer. Cancerous tumors found in the colon or rectum also may spread to other parts of the body.

Excluding skin cancers, colorectal cancer is the third most common cancer in both men and women. It is estimated by the American Cancer Society that 148,810 colorectal cancer cases are expected in 2008. The number of deaths due to colorectal cancer has decreased, which is attributed to increased screening and polyp removal.

What are the symptoms of colorectal cancer?

The following are the most common symptoms of colorectal cancer. However, each individual may experience symptoms differently.

People who have any of the following symptoms should check with their physicians, especially if they are over 50 years old or have a personal or family history of the disease:

a change in bowel habits such as diarrhea, constipation, or narrowing of the stool that lasts for more than a few days
rectal bleeding or blood in the stool
cramping or gnawing stomach pain
decreased appetite
vomiting
weakness and fatigue
jaundice - yellowing of the skin and eyes

The symptoms of colorectal cancer may resemble other conditions, such as infections, hemorrhoids, and inflammatory bowel disease. It is also possible to have colon cancer and not have any symptoms. Always consult your physician for a diagnosis.

What are the risk factors for colorectal cancer?

Risk factors may include:

age — Most people who have colorectal cancer are over age 50, however, it can occur at any age.
diet — Colorectal cancer is often associated with a diet high in fat and calories, and low in fiber.

polyps — Benign growths on the wall of the colon or rectum are common in people over age 50, and are believed to lead to colorectal cancer.
personal history — People who have had colorectal cancer or a history of adenomatous polyps have an increased risk for colorectal cancer.
family history — People with a strong family history of colorectal cancer or polyps in a first-degree relative (in a parent or sibling before the age of 60 or in two first-degree relatives of any age), have an increased risk for colorectal cancer.
ulcerative colitis — People who have ulcerative colitis, an inflamed lining of the colon, have an increased risk for colorectal cancer.
obesity
physical inactivity
alcohol consumption
diabetes

What causes colorectal cancer?

The exact cause of most colorectal cancer is unknown, but the known risk factors listed above are the most likely causes. A small percentage of colorectal cancers are caused by inherited gene mutations. People with a family history of colorectal cancer may wish to consider genetic testing. The American Cancer Society suggests that anyone undergoing such tests have access to a physician or geneticist qualified to explain the significance of these test results.

Persons with a family history of colorectal cancer may wish to consider genetic testing. The American Cancer Society suggests that anyone undergoing such tests have access to a physician or geneticist qualified to explain the significance of the results.

Click here to find out more about methods of screening for colorectal cancer »

Diagnostic procedures for colorectal cancer

In addition to a complete medical history and physical examination, diagnostic procedures for colorectal cancer may include the following:

digital rectal examination (DRE) - a physician or healthcare provider inserts a gloved and lubricated finger into the rectum to feel for anything unusual or abnormal. This test can detect cancers of the rectum, but not the colon.
fecal occult blood test - checks for hidden (occult) blood in the stool. It involves placing a very small amount of stool on a special card, which is then tested in the physician's office or sent to a laboratory.
sigmoidoscopy - a diagnostic procedure that allows the physician to examine the inside of a portion of the large intestine. A short, flexible, lighted tube, called a sigmoidoscope, is inserted into the intestine through the rectum. The scope blows air into the intestine to inflate it and make viewing the inside easier.
colonoscopy - a procedure that allows the physician to view the entire length of the large intestine. It involves inserting a colonoscope, a long, flexible, lighted tube, in through the rectum up into the colon. The colonoscope allows the physician to see the lining of the colon, remove tissue for further examination, and possibly treat some problems that are discovered.
barium enema - a fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray) is given into the rectum to partially fill up the colon. An x-ray of the abdomen shows strictures (narrowed areas), obstructions (blockages), and other problems.
biopsy - a procedure in which tissue samples are removed (with a needle or during surgery) from the body for examination under a microscope; to determine if cancer or other abnormal cells are present.
blood count - to check for anemia (a result of bleeding from a tumor).