Frequently Asked Questions About Colorectal Cancer Screening
The following frequently asked questions will help explain what colorectal cancer is, and the various screening tests available.
- What is colorectal cancer?
- Should I be screened for colorectal cancer?
- Why should I have a colonoscopy?
- Is there anything I can do to reduce my risk for this cancer?
- What are the symptoms?
- How does colorectal cancer affect people in the U.S.?
- What is cancer screening?
Types of Colorectal Cancer Screenings
- What are the screening tests for colorectal cancer?
- How do I know which screening test is right for me?
Getting Ready for a Colorectal Cancer Screening
- How do I prepare for a colonoscopy?
- Will I need to miss work? Will I need someone to drive me home?
- What happens if a screening test shows an abnormality?
- Is colorectal cancer screening covered by insurance?
- What are the Medicare Preventive Service benefits for colorectal cancer screening?
Cancer is a group of diseases in which there is abnormal and uncontrolled growth of cells in the body. If left untreated, cancer cells can spread to other parts of the body.
"Colorectal" refers to the colon and rectum. They make up the large intestine. This type of cancer can begin anywhere in the large intestine. Most of these cancers begin as pre-cancerous abnormal growths (polyps) inside the colon or rectum.
The exact causes of colorectal cancer are not known. However, studies have shown that certain factors are linked to an increased chance of developing this disease. The following groups of people are at high-risk and should be screened for colorectal cancer:
- Age 50 or above: Colorectal cancer is more likely to occur as people get older. Although this disease can occur at any age, most people who develop colorectal cancer are over age 50.
- Family history of colorectal cancer: Close relatives (parents, siblings, or children) of a person who has had colorectal cancer are more likely to develop this type of cancer, especially if the family member developed the cancer at a young age. If many family members have had colorectal cancer, the chances increase even more.
- Personal history of colorectal cancer: A person who has already had colorectal cancer is at an increased risk of developing colorectal cancer a second time.
- Ulcerative colitis or Crohn colitis: People who have ulcerative colitis or Crohn colitis may be more likely to develop colorectal cancer than people who do not have these conditions.
- Familial adenomatous polyposis (FAP): FAP is a rare, inherited condition. Because individuals with this condition are extremely likely to develop colorectal cancer, they are often treated with surgery to remove the colon and rectum in an operation called a colectomy.
Talk with your practitioner if you have any of the above factors that put you at high-risk for developing colorectal cancer. You may need to be screened before the recommended 50 years of age.
Colonoscopy is used to prevent colorectal cancer from developing. The test can find inflamed tissue, ulcers, and polyps which may lead to colorectal cancer. Screening tests find cancer early, when treatment works best and the chance to recover fully is very high. It can help doctors diagnose unexplained changes in bowel habits, abdominal pain, bleeding from the rectum, and weight loss.
There is strong data that supports the idea that having regular screening tests for colorectal cancer starting at age 50 reduces deaths. Screening tests can find polyps before they become cancer in the colon and rectum. The polyps can be removed at that time before they can grow and develop into a colorectal cancer.
Studies have also shown that increased physical activity and keeping a healthy weight can decrease the risk for colorectal cancer. Studies are less clear about other ways to prevent colorectal cancer.
Mainly, the best way to reduce your risk of colorectal cancer is by having regular colorectal cancer screening tests starting at age 50.
People who have polyps or this type of cancer don't usually have symptoms, especially at first. Someone could have polyps or cancer and not know it. If there are symptoms, they may include
- Blood in or on your stool (bowel movement)
- Pains, aches, or cramps in your stomach that don't go away
- Losing weight and you don't know why
- Change in bowel habits (constipation or diarrhea)
If you have any of these symptoms, talk to your health care provider. These symptoms may be caused by something other than cancer. But, the only way to know what is causing them is to see your health care provider.
Of cancers that affect both men and women, this cancer is the second leading cancer killer in the U.S. In 2005, the Centers for Disease Control and Prevention (CDC) reported that 141,405 adults were diagnosed with colorectal cancer. They reported that 53,005 adults died of the disease in the United States.
Screening is using a test to look for a disease before there are any symptoms. Cancer screening tests, including those for colorectal cancer, detect cancer early or find pre-cancerous polyps that can be removed. Finding cancer early can lead to more effective treatment. Diagnostic tests, on the other hand, are used when a person has symptoms. They are used to find out what is causing the symptoms.
Types of Colorectal Cancer Screenings
UW Health suggests colorectal cancer screening for men and women starting at age 50 using optical colonoscopy or virtual colonoscopy.
Several screening tests can be used to find polyps or colorectal cancer. Each can be used alone. Sometimes they are used in combination.
In addition to optical and virtual colonoscopies, flexible sigmoidoscopy is available for screening. Immunochemical Fecal Occult Blood Test (iFOBT) is used to detect blood in the stool. Talk to your health care provider about which test or tests are right for you.
- Optical colonoscopy (screens entire colon): The rectum and total colon are looked at using a flexible tube with a built in camera and light. The patient is sedated. This tube is called a colonoscope. Growths that are not normal can be found and removed or biopsied. How often: Every 10 years.
- Virtual colonoscopy (screens entire colon): A CAT scan of the abdomen is done while carbon dioxide is put into the colon. Special computer software builds a 3-D model of the total colon and rectum. This is viewed by a radiologist to look for colon polyps and cancer. How often: Every 5 years.
- Flexible sigmoidoscopy (screens part of the colon): A flexible, lighted tube (endoscope) is used to view the lining of the lower third of the colon and rectum. How often: Every 5 years.
- iFOBT (does not screen the colon): This test checks for unseen blood in the stool. The test can be done at your clinic or at home. You collect a stool sample on a stick and return the stick to the lab at your clinic, or mail the stick to your health care provider's lab if done at home. If blood is found in the stool, more testing is needed. How often: Once a year.
At this time, data do not suggest that there is a single "best test" for any one person. Each test has advantages and disadvantages. Patients and their health care providers are encouraged to discuss the benefits and potential risks associated with each screening option as they decide which test to use and how often to be tested. Which test to use depends on:
- Your preferences
- Your medical condition
- The likelihood that you will have the test
- The resources for testing and follow-up
- Your risk for colorectal cancer
Getting Ready for a Colorectal Cancer Screening
The health care provider will give you instructions to read carefully a few days before the exam. You may need to shop for special supplies and get laxatives from a drugstore. Many people think the bowel preparation (often called the "bowel prep") the most unpleasant part of the test. You will follow a special diet the day before the exam. You will need to take a very strong laxative before the exam. Sometimes enemas are needed to clean out the colon. The key to getting good pictures during the exam is to have the colon cleaned out.
Because optical colonoscopy is most often done with drugs that make a patient drowsy, you will need to have someone drive you home. People often will miss a day of work after an optical colonoscopy. Virtual colonoscopy does not require having someone drive you, or missing a day of work because drugs that make a person drowsy (sedation) are not used. If the virtual colonoscopy shows polyps and they need to be removed through optical colonoscopy, then you may miss part of a day of work. For the flexible sigmoidoscopy exam and iFOBT, you do not need a driver or to miss any days of work because sedation is not used.
If a screening test finds a problem, more tests may be needed. These tests may include x-rays of the gastrointestinal tract, sigmoidoscopy, or, most often, colonoscopy.
If the iFOBT is positive you will need a follow-up colonoscopy.
If an abnormality is found during a sigmoidoscopy, a biopsy or removal of a polyp may be done during the test.
An optical colonoscopy may be recommended. If an abnormality is found during a standard colonoscopy, a biopsy or removal of the polyp is done to find out if cancer is present and remove any polyps.
If an abnormality is found during a virtual colonoscopy, most patients would be referred for an optical colonoscopy the same day.
Most insurance plans help pay for colorectal cancer screening tests for people aged 50 or older. Many plans also help pay for screening tests for people younger than 50 who are at increased risk for colorectal cancer. Check with your health insurance provider to find out about your colorectal cancer screening benefits. For questions about coverage for virtual colonoscopy contact the Virtual Colonoscopy Office.
People with Medicare who are aged 50 or older are eligible for colorectal cancer screening. Medicare will cover some virtual colonoscopy exams if specific criteria is met. For questions about coverage for virtual colonoscopy contact the Virtual Colonoscopy Office. For more information about Medicare's coverage related to colorectal cancer screening, call the Centers for Medicare and Medicaid Services at 1-800-MEDICARE (1-800-633-4227) (TTY users should call 1-877-486-2048) or visit the Medicare Web site.
Information taken from the Centers for Disease Control and Prevention (CDC) with supplemental information from the National Institutes of Health (NIH), American Cancer Society (ACS), and UW-Health Preventive Health Guideline.