Colorectal Cancer

Colorectal cancer is cancer that starts in the colon or the rectum, which are parts of the large intestine. Depending on where it starts, colorectal cancer might be called “colon cancer” or “rectal cancer.” The two cancers are grouped together because they have many features in common.

Colorectal cancer commonly starts as a growth called a polyp on the inner lining of the rectum or colon. Some types of polyps are not cancerous, but others can change into cancer over time.

Apart from skin cancers, colorectal cancer is the third most diagnosed cancer in both men and women in the United States, and it is the second leading cause of cancer death when numbers for both men and women are combined.

Diagnosis

Since the chances of survival lessen as the cancer spreads, early detection is key to successful treatment. It is recommended that those at average risk be screened regularly starting at age 50. Those with a family history of colorectal cancer should talk with a doctor about the possibility of earlier testing.

Types of screening tests include:

Flexible sigmoidoscopy (or “flex-sig”): A sigmoidoscope, a lighted tube about the thickness of a finger, is inserted through the rectum into the lower part of the colon to check for cancer or polyps. This exam evaluates about one-third of the colon.

Colonoscopy: A small lighted tube with a video camera on the end is used to examine the rectum and colon. This lets the doctor see the entire colon.

Virtual colonoscopy (also known as CT colonoscopy): A tube is inserted in the rectum, air is pumped in to inflate the bowel, and a CT scan is used to create two-dimensional and three-dimensional images.

Stool blood test: A lab tests samples of the stool to look for blood, which indicates the possibility of cancer.

Barium enema: A substance that will show up on X-ray is given as an enema, and air is pumped into the colon, causing it to expand. This process allows abnormalities to show up on X-ray film.

If an abnormality turns up in one of these tests, a doctor might remove a polyp or take a biopsy in order to test for cancer.

Symptoms

Screening is crucial because colon cancer might develop undetected for some time before symptoms arise. Symptoms can include:

• Blood in the stool or rectal bleeding.
• Unexplained weight loss.
• Abdominal pain and tenderness in the lower abdomen.
• Diarrhea, constipation or other changes in bowel habits that last more than a few days.
• Narrow stools.
• Weakness and fatigue.The feeling that a bowel movement has not emptied the bowel completely.

Treatment

Depending on the stage of the cancer when it’s found, treatment options might include surgery to remove the tumor; chemotherapy or radiation to kill the cancer; and targeted therapy, which uses drugs that target specific genes and proteins in cancer cells.

More information

American Cancer Society: Extensive information about colorectal cancer causes, prevention and treatment.

www.cancer.org, 800-227-2345