A colorectal polyp is a growth on the lining of the colon or rectum.
Polyps of the colon and rectum are most often benign. This means they are not a cancer. 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 polyps, which rarely, if ever, develop into cancer
- Serrated polyps, which are 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)
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
Exams and Tests
Your 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:
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.
The outlook is excellent if the polyps are removed. Polyps that are not removed can develop into cancer over time.
When to Contact a Medical Professional
Contact your provider if you have:
- Blood in a bowel movement
- Change in bowel habits
To reduce your risk of developing polyps:
- Eat foods low in fat and eat more fruits, vegetables, and fiber.
- Do not smoke and do not 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.
- All adults should begin these tests at age 45.
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.
Intestinal polyps; Polyps - colorectal; Adenomatous polyps; Hyperplastic polyps; Villous adenomas; Serrated polyp; Serrated adenoma; Precancerous polyps; Colon cancer - polyps; Bleeding - colorectal polyps
Garber JJ, Chung DC. Colonic polyps and polyposis syndromes. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 126.
National Comprehensive Cancer Network website. NCCN clinical practice guidelines in oncology (NCCN guidelines): colorectal cancer screening. Version 2.2021. www.nccn.org/professionals/physician_gls/pdf/colorectal_screening.pdf. Updated April 13, 2021. Accessed June 29, 2021.
Qaseem A, Crandall CJ, Mustafa RA, Hicks LA, Wilt TJ, Clinical Guidelines Committee of the American College of Physicians, et al. Screening for colorectal cancer in asymptomatic average-risk adults: a guidance statement from the American College of Physicians. Ann Intern Med. 2019;171(9):643-654. PMID: 31683290 pubmed.ncbi.nlm.nih.gov/31683290/.
Rex DK, Boland CR, Dominitz JA, et al. Colorectal cancer screening: recommendations for physicians and patients from the U.S. Multi-Society Task Force on Colorectal Cancer. Am J Gastroenterol. 2017;112(7):1016-1030. PMID: 28555630 pubmed.ncbi.nlm.nih.gov/28555630/.
US Preventive Services Task Force website. Final recommendation statement. Colorectal cancer: screening. www.uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening. Published May 18, 2021. Accessed June 29, 2021.
Review Date 1/12/2020
Updated by: Michael M. Phillips, MD, Clinical Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Internal review and update on 08/20/2021 by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 08/02/2021.