Colon and Rectal Cancer

Colorectal cancer is the third most common cancer diagnosed in American men and women. About 150,000 new cases of colon or rectal cancer will be diagnosed in 2006. The good news is that deaths from colorectal cancer have decreased in the past 15 years, thanks in part to early detection and improved treatment.

According to the American Cancer Society, the point of colorectal cancer screening to is find polyps and cancers before they cause symptoms. If caught at an early stage, colorectal cancer can be successfully treated; polyp removal may even help prevent cancer.

Starting at age 50, both men and women should follow one of the five testing schedules listed below. If you have any risk factors, talk to your doctor about the possibility of screening earlier. Your doctor can help you decide which tests are most appropriate for you:

1. Yearly fecal occult blood test (FOBT) – using a take-home multiple sample kit -- or fecal immunochemical test ( FIT )
2. Flexible sigmoidoscopy every five years
3. Yearly FOBT or FIT, plus flexible sigmoidoscopy every five years. This combination of tests is preferred over FOBT, FIT or flexible sigmoidoscopy alone.
4. Double-contrast barium enema every five years
5. Colonoscopy every 10 years

**All positive tests should be followed up with colonoscopy.

Yearly Fecal Occult Blood Test (FOBT)

This test is used to find hidden blood in feces. The presence of blood in the stool can indicate the presence of polyps in the digestive tract. If blood is detected, a colonoscopy is needed to determine where the bleeding origins from within the digestive tract. If you have this test, you’ll receive a kit at your doctor’s office with instructions about how to collect the samples. Then you must return the kit to your doctor’s office or to a lab.

If you are having this test, the American Cancer Society recommends avoiding:

• nonsteroidal anti-inflammatory drugs (NSAIDS), such as ibuprofen (Advil), naproxen (Aleve), or aspirin (more than one adult aspirin per day), for seven days before testing (they can cause bleeding)
• vitamin C in excess of 250 mg daily from either supplements or citrus fruits, and juices for three days before testing (they can affect the chemicals in the test and make it show negative)
• red meats for three days before testing (components of blood in the meat may cause the test to show positive)
• raw broccoli, cauliflower, horseradish, parsnips, radishes, turnips and melons for three days (peroxidases in these vegetables may cause the test to show positive)

You can find more information about FOBT in our Health Library »

Back to top

Fecal immunochemical test (FIT)

This test also detects hidden blood in the feces. This is a newer test that is a bit more accurate than the fecal occult blood test. As with FOBT, this test can detect the presence of blood but cannot tell where it originates from. The presence of blood must be followed up with a colonoscopy. Because this test is more specific, vitamins and food do not affect the outcome as they do in the FOBT.

Back to top

Flexible sigmoidoscopy

A sigmoidoscope is a slender, flexible, hollow, lighted tube about the thickness of a finger. It is inserted through the rectum and into the lower part of the colon. Your doctor can look through this scope, and, the scope can be connected to a video camera and display monitor for a better view.  Using the sigmoidoscope, your doctor can view the inside of the rectum and part of the colon to detect any abnormality. Because the sigmoidoscope is only 60 centimeters (around 2 feet) long, the doctor is able to see the entire rectum but less than half of the colon with this procedure. Before the sigmoidoscopy, you will need to have a bowel preparation to clean out your lower colon. If an adenomatous polyp or colorectal cancer is found during the procedure, you will need to have a colonoscopy to look for polyps or cancer in the rest of the colon. This test may be uncomfortable, but it should not be painful, and it takes only 10 to 20 minutes.

You will be awake for the test, but may receive medicine to help you relax during it.

Preparing for a Sigmoidoscopy

Your colon and rectum must be empty and clean so your doctor can see. You may be asked to:

• Use two enemas before the exam.  
• Drink only clear liquids for a day before the exam.

Back to top

Double contrast barium enema

Your colon is x-rayed after your colon is filled with a contrast agent and air to ensure clear pictures. Barium sulfate is a chalky substance used to partially fill and open up the colon. Once barium is spread throughout the colon, air is pumped in to make it expand. The procedure takes 30 to 45 minutes.

Preparing for a Barium Enema

• Have a liquid diet for two days before the procedure and clear liquids the day before the procedure
• Avoid eating or drinking dairy products the day before the test
• Refrain from eating or drinking anything after midnight the night before the procedure
• Clean your bowel the night before with laxatives and take an enema the morning of the exam

Back to top

Colonoscopy

A colonoscope is a long version of a sigmoidoscope. It is inserted through the rectum into the colon and allows your doctor to see the lining of your entire colon. The colonoscope is connected to a video camera and video display monitor so the doctor can see and closely examine the inside of the colon. If you have a colonoscopy, you will need to take laxatives (liquids, pills, or both) the day before the test and possibly an enema that morning to empty and clean your colon.

Preparing for a Colonoscopy

If you’re scheduled for a colonoscopy, you will likely be asked to:

• Drink only clear liquids (water, apple or cranberry juice, and any gelatin except red or purple) for a day or two before the exam.
• Refrain from eating or drinking anything after midnight the night before your test.

Colonoscopy may be done in a hospital outpatient department, in a clinic, or in a doctor's office. The test itself usually takes 15 to 30 minutes, although it may take longer if a polyp is found and removed. You will get an I.V. (intravenous line) so that medicine can be given through a vein. The medicine will relax you and make you feel sleepy. You will probably be awake, but you may not be aware of what is going on and may not remember the procedure afterward. You should arrange for someone to drive you home from the test because the sedative can affect your ability to drive. Depending on the sedatives that are used, some doctors require that someone drive you home. Most people will be fully awake by the time they get home.

Colonoscopy should be done if the FOBT or FIT shows blood in the stool, if sigmoidoscopy results show a polyp, or if double-contrast barium enema studies show anything abnormal. If possible, polyps should be removed during the colonoscopy.  

Back to top

Risk Factors

Talk to your doctor about starting colorectal cancer screening earlier or more often if you have any of these risk factors:

• Age: While younger adults can develop colorectal cancer, your chances of developing colorectal cancer increase markedly after age 50. More than 90 percent of people diagnosed with colorectal cancer are older than 50.
• A personal history of colorectal cancer: If you have had colorectal cancer, even though it has been completely removed, you are more likely to develop new cancers in other areas of the colon and rectum. The chances of this happening are greater if you had your first colorectal cancer when you were age 60 or younger.
• A personal history of colorectal polyps: If you have had an adenomatous-type polyp, you are at increased risk of developing colorectal cancer. This is especially true if the polyps are large or if there are many of them.
• A personal history of chronic inflammatory bowel disease: Chronic inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is a condition in which the colon is inflamed over a long period of time. If you have chronic inflammatory bowel disease, your risk of developing colorectal cancer is increased.
• A family history of colorectal cancer: Most colorectal cancers occur in people without a family history of colorectal cancer. However, if you have a family history of colorectal cancer or adenomatous polyps in any first-degree relative (a sibling or parent) younger than age 60, or in two or more first-degree relatives at any age are considered at increased risk for the disease. (First-degree relatives are defined as parents, siblings, and children.)
• Inherited disease: About 10 percent of people who develop colorectal cancer have an inherited genetic susceptibility to the disease. Inherited colorectal syndromes can include hereditary non-polyposis colorectal cancer (HNPCC), or Lynch syndrome, familial adenomatous polyposis (FAP), or hereditary nonpolyposis colon cancer (HNPCC). If other members of your family have these diseases, you should talk to your doctor about aggressive screening for yourself.
• Ethnic background: Jewish people of Eastern European descent (Ashkenazi Jews) have a higher rate of colorectal cancer – the result of a genetic mutation that is present in about six percent of American Jews. This gene change is called the I1307K APC mutation.
• A diet mostly from animal sources: A high-fat diet can increase your risk of colorectal cancer. Eating red meat and processed meats will increase colorectal cancer risk over time. The American Cancer Society also recommends eating at least five servings of fruits and vegetables every day and several servings of other foods from plant sources, such as breads, cereals, grain products, rice, pasta, or beans. Many fruits and vegetables contain substances that interfere with the process of cancer formation.
• Physical inactivity: If you are not physically active, you have a greater chance of developing colorectal cancer.
• Obesity: If you are very overweight, your risk of dying from colorectal cancer is increased.
• Smoking: Recent studies indicate that smokers are 30 to 40 percent more likely than non-smokers to die from colorectal cancer. Smoking not only causes cancers of the lung, mouth and larynx; some cancer-causing substances are swallowed and can cause digestive system cancers.
• Alcohol intake: Colorectal cancer has been linked to the heavy use of alcohol. While some of this may be due to the effects of alcohol on folic acid in the body, it still would be wise to avoid heavy alcohol use.

Back to top