During a colonoscopy, your doctor guides a thin tube with a light and a camera through the
colon and rectum to look for polyps or signs of cancer. This procedure allows your doctor to
remove polyps or take tissue samples when extra testing is needed.
This test requires bowel prep ahead of time to clean out your colon and uses general
anesthesia so that you are asleep during the procedure. If you don’t have any risk factors for
colorectal cancer, it’s recommended that you get a colonoscopy every ten years.
Double contrast barium enema (DCBE)
A double contrast barium enema is an imaging test sometimes used to look for polyps or
cancer in the rectum. It uses X-rays to create images of the colon and rectum. During this test,
the radiology technician injects barium into the rectum to coat it, which makes the colon and
rectum more visible on the X-ray.
A sigmoidoscopy lets your doctor look at the inside of your rectum and the bottom portion of
your colon. During a flexible sigmoidoscopy, a thin tube with a camera and a light is guided
through the intestinal tract, much like a colonoscopy.
Sigmoidoscopy only looks at the bottom portion of the colon. As a result, it isn’t a common
choice for colorectal screening. If you choose this test, you’ll need to do an enema bowel prep
beforehand. Frequently, it is used as a screening tool for individuals who have undergone a
prior operation that removed almost all sections of the colon.
Stool tests for rectal cancer let you collect samples of your stool from the comfort of your home
and send them to the lab to detect signs of cancer. A few stool tests for
colorectal cancer look for blood, DNA or both in the stool. These tests have limited capacities,
including the possibility of a false positive or a missed polyp or tumor. Talk with your doctor to
understand the benefits and drawbacks of stool tests.
- Guaiac-based fecal occult blood test (gFOBT): A fecal occult blood test looks for
hidden blood in the stool, which could be a sign of rectal cancer or other digestive
conditions. This test is recommended every year as a screening for colorectal cancer.
Before taking stool samples, your doctor may ask you to limit certain foods, like red
meats, or stop taking certain medications, especially iron.
- Fecal immunochemical test (FIT): A FIT test looks for signs of blood in the stool to
help detect colorectal cancer. You’ll receive a kit to collect multiple samples at home,
and you typically don’t need to change your diet or medications before the test. For
screening, FIT is recommended every three years.
- Stool DNA test: A stool DNA test looks for hidden blood in the stool and DNA
pieces that might indicate the presence of polyps or cancer. This type of stool test
doesn’t require diet or medication changes, and it’s recommended every three years.
You may choose to have a virtual colonoscopy every five years to screen for rectal cancer. This
exam uses CT imaging while you are awake to provide images of the colon and rectum and look
for signs of cancer. Like a colonoscopy, a virtual colonoscopy requires bowel prep ahead of time
to clean out the intestinal tract and provide a clear view of your colon and rectum. If a lesion is
identified on the CT scan, a colonoscopy will be necessary to biopsy or remove the tissue.