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Commonly Asked Questions About Colon Cancer Screening

Answered by gastroenterologists in the Digestive Disease Center at Beth Israel Deaconess Medical Center.

Who needs to be screened for colon cancer?

The National Cancer Institute, the National Cancer Society and many other esteemed medical organizations recommend routine colon cancer screening for both men and women beginning at age 50. While there are a number of different methods to check for early signs of colon cancer, at Beth Israel Deaconess Medical Center we believe colonoscopy is the best test available because doctors can view virtually the entire colon and eliminate polyps that can lead to cancer.

For those at average risk of colon cancer, colonoscopy should be performed at age 50 and every 10 years after that. Those at high risk need more frequent testing. High risk individuals include those who have a family history of colorectal cancer, have had the disease themselves or have had previous screening tests that have turned up polyps or other early signs of cancer. Those who also have certain inflammatory bowel diseases, such as ulcerative colitis or Crohn's disease are also at higher risk. In addition, we recommend that African-American men and women also get tested earlier, at age 45, as they have a higher incidence of the disease. However, insurance may not pay for this earlier screening. Talk to your doctor about when you should schedule your colonoscopy.

stages of colon cancer

Finally, there are very few early warning signs of colorectal cancer. If you notice any concerning changes in bowel habits including blood in your stool, you should see your doctor immediately.

Why get screened?

Colonoscopy allows doctors to find and remove pre-cancerous polyps in the colon and rectum before they become cancerous. By finding these polyps earlier you can prevent colon cancer and if colon cancer is detected it may be easier to treat. It's a screening tool that has been proven to save lives.

How do I prepare for my colonoscopy?

Preparing for the colonoscopy is often the most uncomfortable part of the process for many people. In order to allow the doctor a clear view during the colonoscopy, it is very important that the entire colon is emptied out and clean. Any additional residue in the colon will make it harder for the doctor to check for abnormal tissue. After you make your appointment, you will be given a procedure to follow in the days leading up to your test. You typically cannot eat or drink anything after midnight on the night before the test. Preparation will also include:

  • Drinking a special solution that will clean out the colon.
  • Low fiber diet for 7 days.
  • Clear liquids only the day before the procedure.
  • Avoiding liquids with red or purple dye.
  • Avoiding certain medications or altering the dosages of some medications.

You should plan on being near a bathroom the day prior to your colonoscopy. Most people go to the bathroom multiple times in the 24 hours prior to the screening.

How will the test feel?

You will be given a sedative and pain medication to relax you and make you feel drowsy. Many patients do not remember having the colonoscopy. When the colonoscope is inserted, you may feel pressure. As the air as inserted, many people pass gas or feel some cramping. Once the doctor begins, the colonoscopy typically takes less than 30 minutes.

colonoscopy diagram

What is a polyp and what happens if they find one?

A polyp is a growth on the surface of a colon. Polyps can be raised or flat. While most polyps are not cancerous, but rather are pre-cancerous, meaning that some could become cancerous in the future, it is important to have your colonoscopy so that doctors can find and remove them early. Doctors will typically remove any polyp found during the colonoscopy. If doctors see a very large polyp or other abnormal tissue during the colonoscopy, they will typically take a biopsy find out more about the lesions.

If they find a polyp or lesion, is it definitely cancer?

colon polypNo. Most colon polyps are benign, and doctors will typically remove polyps if they are found during your colonoscopy. It is essential that all polyps are removed because even those that are pre-cancerous have the potential to turn into cancer in the future.

Are there risks?

There are risks with any medical procedure. Although uncommon, complications of colonoscopy can include bleeding and or tearing/perforation of the lining of the colon. It's important to make sure the physician who performs the test is experienced, to limit the chance of a complication. We believe the benefits of being screened for colon cancer outweighs the risks of having the procedure.

Can I work the next day?

Although you will need to take the day of your colonoscopy off from work because you may still feel woozy from the sedatives, you can generally expect to resume your normal routine and work the next day.

What if the colonoscopy shows something abnormal?

The doctor will biopsy the abnormal tissue, and have it tested for cancerous cells. He or she will then meet with you to go over the results and explain next steps.

What if I schedule my colonoscopy, but get so nervous I decide I just can't do it?

We understand that this test is not something you'll look forward to. If you find yourself becoming anxious as the date approaches, we suggest you talk to others who have had the test about their experience with it. If you absolutely decide you can't go through with it, talk to your doctor about other types of screening tests.

Above content provided by Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.

Posted September 2010

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Digestive Disease Center
Beth Israel Deaconess Medical Center
Boston, MA 02215

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Call 1-800-667-5356. Representatives are available to assist you live 8:30 a.m. - 5 p.m., Monday through Friday.