Colon polyps are growths on the lining of your colon or large intestine, part of your digestive tract. Most of them aren’t harmful. But some can turn into colon cancer over time. For that reason, your doctor needs to take out any colon polyps you have.
What Causes Colon Polyps?
Doctors don’t know exactly why they form. Normally, cells grow and divide in a specific way. Polyps may happen when cells grow and divide more than they should.
Anyone can get colon polyps, but certain things make you more likely to have them, including if you:
- Are overweight or obese
- Are age 50 or older
- Have had colon polyps or colon cancer before
- Have an inflammatory bowel disease, like ulcerative colitis or Crohn’s disease
- Have type 2 diabetes that isn’t well-controlled
Some genetic conditions also raise your chances for polyps and colon cancer, including:
- Familial adenomatous polyposis (FAP). This can cause hundreds or thousands of polyps to grow when you’re young, as early as your teenage years.
- Gardner’s syndrome. This is a type of FAP that causes polyps to grow in your colon and small intestine. It may also cause noncancerous tumors in other parts of your body.
- Lynch syndrome. Also known as hereditary nonpolyposis colorectal cancer or HNPCC, it causes polyps that are very likely to become colon cancer.
- MYH-associated polyposis (MAP). A problem with the MYH gene causes many polyps to grow or colon cancer to happen at a young age.
- Peutz-Jeghers syndrome. The condition starts with freckles that show up all over the body. It also causes colon polyps that can become cancer.
- Serrated polyposis syndrome. This causes a specific type of polyp, serrated adenomatous polyps, to grow in the upper part of the colon. They can turn into colon cancer.
If you have one of these conditions, your doctor will recommend regular screening tests to look for problems early.
What Are the Types of Polyps?
Not all polyps are the same. There are two main kinds:
Hyperplastic. This type is unlikely to become cancer.
Adenoma. Most colon cancer starts as this type, though not all adenomas will become harmful. Under a microscope, adenomas look different based on how they grow. Doctors divide them into subtypes based on their growth patterns:
In general, the larger an adenoma, the more likely it is to become cancer.
Most colon polyps don’t cause symptoms. You probably won’t know you have one unless a test finds it. If you do have signs, they can include:
- Blood in your poop, in the toilet bowl, or on toilet paper when you wipe. These could be signs of bleeding inside your colon.
- A bowel movement that's black or has red streaks, which may mean there’s blood in it
- Constipation or diarrhea that lasts longer than a week
- Belly pain
- Fatigue or shortness of breath. These can be signs that your body doesn’t have enough iron, which can happen if polyps bleed.
Talk to your doctor if you notice any of these signs. They don’t always mean that you have colon polyps or colon cancer. Other things like hemorrhoids, tears in the tissue inside your bottom, or some medicines can cause these symptoms.
How to Find Colon Polyps
It’s important to spot polyps early to prevent colorectal cancer. There are several kinds of screening tests. Your doctor can also take out polyps during some of them.
Screening tests for colon polyps include:
- Colonoscopy. About 1 to 3 days before the test, you’ll go on a clear liquid diet and take a laxative to clear out your colon. Your doctor will give you medicine so you’re not awake during the procedure. They use a long, thin, flexible tube with a light and camera at the end to look at the inside of your colon. They can also remove most polyps and send them to a lab to check for cancer. This test takes about 30 minutes.
- CT colonography. Also known as a virtual colonoscopy, this uses X-rays and a computer to take pictures of your colon from outside your body. Your doctor can’t take polyps out during this test. If they spot any, you’ll need to have a regular colonoscopy. You’re awake for this test, but you’ll still need to do a special diet to clear out your bowel beforehand.
- Flexible sigmoidoscopy. This test is similar to a colonoscopy, but you don’t have to do as much bowel prep. You might take medicine that helps you relax during the procedure. Your doctor puts a thin tube with a light into your bottom to look only at the lower part of your colon. If you have a polyp, they can remove it during the test. It takes about 20 minutes.
- Stool tests. A FOBT (guaiac-based fecal occult blood test) and a FIT (fecal immunochemical test) look for tiny traces of blood in your poop. Stool DNA tests check for gene changes. For any of these tests, you collect a poop sample at home and take it to your doctor’s office or send it to a lab. If the tests find problems, you’ll need to have a colonoscopy.
- Lower gastrointestinal series. Also called a barium enema. Before this test, the radiologist will fill your large intestine with a chalky liquid called barium, which makes your colon easier to see during an X-ray.
Treatments for Colon Polyps
During a colonoscopy or flexible sigmoidoscopy, your doctor uses forceps or a wire loop to remove polyps. This is called a polypectomy. If the polyp is too large to take out this way, you may need surgery to remove it. Once it’s out, a pathologist tests it for cancer.
If you have a genetic condition like familial adenomatous polyposis, your doctor may recommend surgery to remove part or all of your colon and rectum. That’s the best way to prevent colon cancer for people with these health problems.
If you have colon polyps, there’s a good chance you’ll get more of them later on. Your doctor will recommend that you have more screening tests later on.
How Can I Prevent Colon Polyps?
Healthy habits can lower your odds of having colon polyps. For example, you should:
- Eat a diet with lots of fruits, vegetables, and fiber-rich foods like beans, lentils, peas, and high-fiber cereal.
- Lose weight if you’re overweight.
- Limit red meat, processed meats, and foods that are high in fat.
- Talk to your doctor about whether calcium and vitamin D supplements are right for you. Some studies suggest they could lower your odds of colon cancer, but others don't.
- If you have a family history of colon polyps, ask your doctor if you should get genetic counseling and when you should start screening for polyps.
- Talk to your doctor about taking aspirin regularly. There is some evidence that aspirin has a preventive effect against colon cancer.