Polyps of the colon and rectum are most often benign. This means they are not a cancer and do not spread. You may have one or many polyps. They become more common with age. There are many types of polyps.
Adenomatous polyps are a common type. They are gland-like growths that develop on the mucous membrane that lines the large intestine. They are also called adenomas and are most often one of the following:
- Tubular polyp, which protrudes out in the lumen (open space) of the colon
- Villous adenoma, which is sometimes flat and spreading, and is more likely to become a cancer
When adenomas become cancerous, they are known as adenocarcinomas. Adenocarcinomas are cancers that originate in glandular tissue cells. Adenocarcinoma is the most common type of colorectal cancer.
Other types of polyps are:
- Hyperplastic polyp, which rarely, if ever, develop into cancer
- Serrated polyp, which is less common, but may develop into cancer over time
Polyps bigger than 1 centimeter (cm) have a higher cancer risk than polyps smaller than 1 centimeter. Risk factors include:
- Family history of colon cancer or polyps
- A type of polyp called villous adenoma
A small number of people with polyps may also be linked to some inherited disorders, including:
- Familial adenomatous polyposis (FAP)
- Gardner syndrome (a type of FAP)
- Juvenile polyposis (disease that causes many benign growths in the intestine, usually before 20 years old)
- Lynch syndrome (HNPCC, a disease that raises the chance of many types of cancer, including in the intestine)
- Peutz-Jeghers syndrome (disease that causes intestinal polyps, usually in the small intestine and usually benign)
A colorectal polyp is a growth on the lining of the colon or rectum.
Exams and Tests
The health care provider will perform a physical exam. A large polyp in the rectum may be felt during a rectal exam.
Most polyps are found with the following tests:
- Barium enema (rarely done)
- Stool test for hidden (occult) blood
- Virtual colonoscopy
- Stool DNA test
Outlook is excellent if the polyps are removed. Polyps that are not removed can develop into cancer over time.
To reduce your risk of developing polyps:
- Eat foods low in fat and eat more fruits, vegetables, and fiber.
- Do not smoke or drink alcohol in excess.
- Maintain a normal body weight.
- Get regular exercise.
Your provider can order a colonoscopy or other screening tests:
- These tests help prevent colon cancer by finding and removing polyps before they become cancer. This may reduce the chance of developing colon cancer, or at least help catch it in its most treatable stage.
- Most people should begin these tests at age 50. Those with a family history of colon cancer or colon polyps may need to be screened at an earlier age or more often.
Taking aspirin, naproxen, ibuprofen, or similar medicines may help reduce the risk for new polyps. Be aware that these medicines can have serious side effects if taken for a long time. Side effects include bleeding in the stomach or colon and heart disease. Talk with your provider before taking these medicines.
Polyps usually do not have symptoms. When present, symptoms may include:
- Blood in the stools
- Change in bowel habit
- Fatigue caused by losing blood over time
Colorectal polyps should be removed because some can develop into cancer. In most cases, the polyps may be removed during a colonoscopy.
For people with adenomatous polyps, new polyps can appear in the future. You should have a repeat colonoscopy usually 1 to 10 years later, depending on:
- Your age and general health
- Number of polyps you had
- Size and type of the polyps
- Family history of polyps or cancer
In rare cases, when polyps are very likely to turn into cancer or too large to remove during colonoscopy, the provider will recommend a colectomy. This is surgery to remove part of the colon that has the polyps.
When to Contact a Medical Professional
Call your provider if you have:
- Blood in a bowel movement
- Change in bowel habit
American Gastroenterological Association. Early detection of colorectal cancer (CRC) and adenomatous polyps clinical decision support tool. Gastroenterology. 2014;147(4):925-926. PMID: 25151575
Itzkowitz SH, Potack J. Colonic polyps and polyposis syndromes. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology/Diagnosis/Management. 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 126.
Lieberman DA, Rex DK, Winawer SJ, Giardiello FM, Johnson DA, Levin TR; United States Multi-Society Task Force on Colorectal Cancer. Guidelines for colonoscopy surveillance after screening and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2012;143(3):844-857. PMID: 22763141
National Comprehensive Cancer Network website. NCCN clinical practice guidelines in oncology (NCCN guidelines): colorectal cancer screening. Version 2.2017.