Colorectal Cancer Screening

Colorectal cancer is one of the easiest cancers to treat when caught early. Regular screenings are the best way to do this. Colon cancer screening methods range from simple tests you can do at home to more involved procedures in a doctor’s office.

The most accurate and comprehensive way to screen for colorectal cancer remains the colonoscopy. This is a procedure that can detect cancer as well as treat it in its earliest stages. However, if you are unable to undergo a colonoscopy, your physician can recommend alternative screening methods.

Screening guidelines for average-risk patients

Patients who carry an average risk of colorectal cancer usually begin regular screenings at age 45. An “average risk” of colon cancer generally means that:

  • You have never had colorectal cancer or colon polyps
  • You have no family history of colorectal cancer
  • You don’t have an inflammatory bowel disease (such as Crohn’s or ulcerative colitis)

Screening guidelines for higher-risk patients

Patients who have a higher risk of colorectal cancer will need to start screenings earlier. Higher-risk patients are typically individuals who:

  • Have a strong family history of colorectal cancer
  • Have a hereditary colorectal cancer syndrome
  • Have an inflammatory bowel disease

Higher-risk patients should generally begin screening 10 years before the earliest colorectal cancer diagnosis in their family. For instance, a patient whose father developed colorectal cancer at age 45 would start screenings at age 35.

Screening tests for colorectal cancer

Your physician will likely recommend a particular type of screening based on your age, risk factors, health and personal preferences. The most common options are listed below. Keep in mind that you’ll need to repeat certain screening methods more frequently than others.

How often do I need to be screened?

The frequency at which you’ll need to repeat colorectal cancer screening depends on the type of test:

  • Stool-based test: every year
  • Colonoscopy: every ten years
  • Virtual colonoscopy: every five years
  • Flexible sigmoidoscopy: every five years

Stool-based tests

These tests are a convenient way to learn if you are passing blood in your stools. Blood in the stool can be a key indicator of colorectal cancer, but it’s not always visible to the eye. Your physician may recommend that you take one of these tests as a simple screening for colorectal cancer.

How are stool-based tests performed? What types of stool-based tests are there?

To perform the test, you will collect multiple stool samples and send them off to a laboratory. There, they will be tested for hidden blood.

Stool-based screening tests include:

  • Fecal occult blood test (FOBT)
  • Fecal immunochemical test (FIT, or iFOBT)
  • Colo Gard DNA test 
What if something is found during my stool-based test?

If the test indicates that you do have blood in your stool, you will need to undergo a colonoscopy. This will identify the source of the bleeding and rule out possible colorectal cancer.

Colonoscopy

A colonoscopy is an imaging procedure that can locate pre-cancerous or cancerous growths, called polyps, on the interior lining of the colon. If the polyps are small enough, your doctor can remove them during the test. This prevents them from developing into cancer. Tissue samples can also be collected for biopsies.

How should I prepare for my colonoscopy?

The colon must be entirely clear of stool for the test to be accurate. The night before undergoing a colonoscopy, you’ll need to “prep” your colon by drinking a laxative solution. Though inconvenient and sometimes uncomfortable, completing the prep is critical for the quality of the colonoscopy. Most patients tolerate the prep very well.

What happens during a colonoscopy?

You will be sedated during your colonoscopy. Your doctor will thread a thin, flexible tube with a small camera at the end through the full length of the colon. They will then inspect your colon for polyps or other suspicious areas, which they will remove as necessary. If your colonoscopy reveals anything suspicious, your doctor will take a tissue sample and test it for cancerous cells.

If polyps are found during my colonoscopy, does that mean I'm going to get colorectal cancer?

Most colon polyps are harmless, but some can develop into colorectal cancer over time. Your doctor will be able to tell if a colon polyp is cancerous through a biopsy. What’s great about a colonoscopy is that your doctor can remove polyps right then and there, during your screening.

Do all polyps need to be removed?

Because a small percentage of colon polyps can mutate and develop into cancer, it’s best to have all polyps removed.

Virtual colonoscopy

This is a type of CT scan that creates a 3D image of the inside of the colon. During the test, a doctor inserts a small tube into the rectum to gently inflate the colon with air and scan it. Patients must still complete a colon prep before undergoing a virtual colonoscopy.

How is a virtual colonoscopy different from a colonoscopy?

Unlike a traditional colonoscopy, a virtual colonoscopy isn’t invasive and you don’t need to be sedated during the procedure. A virtual colonoscopy can be a good option for patients who take blood thinners. However, because the imaging takes place from outside the colon, your doctor won’t be able to remove any polyps or tissue. If your virtual colonoscopy reveals polyps, you’ll need a colonoscopy or another follow-up procedure to take them out.

If polyps are found during my virtual colonoscopy, does that mean I'm going to get colorectal cancer?

Most colon polyps are harmless, but some can develop into colorectal cancer over time. Your doctor will be able to tell if a colon polyp is cancerous through a biopsy. Because polyps can’t be removed during a virtual colonoscopy, your doctor may recommend a traditional colonoscopy to collect a tissue sample or remove the polyps.

Do all polyps need to be removed?

Because a small percentage of colon polyps can mutate and develop into cancer, it’s best to have all polyps removed. If your virtual colonoscopy reveals polyps, your doctor may recommend a traditional colonoscopy to collect a tissue sample or remove the polyps.

Flexible sigmoidoscopy

This exam uses a small flexible tube to examine only the lower part of the colon. Patients do not need to be sedated.

Barium enema

This is an X-ray of the colon taken after barium liquid is put into the rectum and colon to check for polyps or other abnormal areas in the colon and rectum. Today, virtual colonoscopy has largely replaced barium enemas.

Where to get screened for colorectal cancer

Gastroenterologists – physicians who specialize in treating the digestive system – usually perform colon cancer screenings. But because most people don’t see a gastroenterologist regularly, the path to screening often begins with a primary care doctor. Talk to your doctor about screening options and gastroenterologists in the area who could perform the test.

How can I make an appointment to see an expert at Siteman?

Washington University’s Division of Gastroenterology is made up of a team of dedicated doctors who are exceptionally skilled at performing colonoscopy. If you have concerns about your colon health, or if you simply want to come in for a routine checkup, please complete this form.

Getting screened without health insurance

Colonoscopies are costly medical procedures. It’s natural to worry that you won’t be able to afford one if you don’t have health insurance.

One option for patients without insurance is to contact their local community health center and ask about colonoscopy screening. Staff should be able to assist you.

In addition, hospitals sometimes offer financial aid for colonoscopies for patients who qualify. Reach out to the hospitals in your area and ask if there are any funds available.

Does Siteman offer financial assistance?

If you are concerned about the cost of cancer screening, we are here to help. BJC HealthCare offers financial assistance to help those who don’t have health insurance. For questions regarding billing, use the appropriate contact information below: