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Patient education: Colon polyps (Beyond the Basics)

Patient education: Colon polyps (Beyond the Basics)
Author:
Chyke Doubeni, MD, FRCS, MPH
Section Editor:
J Thomas Lamont, MD
Deputy Editor:
Shilpa Grover, MD, MPH, AGAF
Literature review current through: Nov 2022. | This topic last updated: Mar 17, 2022.

COLON POLYPS OVERVIEW — The finding of polyps in the colon or rectum often raises questions for patients and their families. What is the significance of finding a polyp? Does this mean that I have, or will develop, colon or rectal (colorectal) cancer? Will a polyp require surgery?

Some types of polyps (called adenomas) have the potential to become cancerous, while others (hyperplastic or inflammatory polyps) have virtually no chance of becoming cancerous.

When considering risk from colon polyps, the following points should be considered:

Polyps are common (they occur in 30 to 50 percent of adults)

Not all polyps will become cancer

It takes many years for a polyp to become cancerous

Polyps can be completely and safely removed

The best course of action when a polyp is found depends upon the number, type, size, and location of the polyp. People who have an adenoma removed will require a follow-up examination as new polyps may develop over time that need to be removed.

COLON POLYP CAUSES — Polyps are very common in males and females of all races who live in industrialized countries, suggesting that dietary and environmental factors play a role in their development.

Lifestyle — Although the exact causes are not completely understood, lifestyle risk factors include the following:

A high-fat diet

A diet high in red meat

A low-fiber diet

Cigarette smoking

Obesity

On the other hand, use of aspirin and other nonsteroidal anti-inflammatory drugs and a high-calcium diet may have a protective effect. (See "Patient education: Screening for colorectal cancer (Beyond the Basics)".)

Aging — Polyps and colorectal cancers are uncommon before age 40. Ninety percent of cases occur after age 50, with males somewhat more likely to develop polyps than females; therefore, colon cancer screening is usually recommended starting at age 50 for both sexes. It takes approximately 10 years for a small polyp to develop into cancer.

Family history and genetics — Polyps and colon cancer tend to run in families, suggesting that genetic factors are important in their development.

Any history of colon polyps or colon cancer in the family should be discussed with a health care provider, particularly if cancer developed at an early age in the family member, in close biological relatives, or in multiple family members. As a general rule, screening for colon cancer begins at an earlier age in people with a family history of cancer or polyps.

Some rare genetic diseases increase the chances of getting colorectal cancer relatively early in adult life. Familial adenomatous polyposis and MUTYH-associated polyposis cause multiple colon polyps. Another hereditary nonpolyposis colon cancer, or Lynch syndrome, increases the risk of polyps and colon cancer. Testing for these genes may be recommended for families with high rates of cancer. People diagnosed with colorectal cancer should have genetic testing, which may identify the presence of some of these conditions.

TYPES OF COLON POLYPS — The most common types of polyps are hyperplastic and adenomatous polyps. Other types of polyps can also be found in the colon, although these are far less common and are not discussed here.

Hyperplastic polyps — Hyperplastic polyps are usually small, located in the end-portion of the colon (the rectum and sigmoid colon), have no potential to become malignant, and are not worrisome (figure 1). It is not always possible to distinguish a hyperplastic polyp from an adenomatous polyp based upon appearance during colonoscopy, which means that hyperplastic polyps are often removed or biopsied to allow microscopic examination.

Adenomatous polyps — Two-thirds of colon polyps are adenomas. Most of these polyps do not develop into cancer, although they have the potential to become cancerous. Adenomas are classified by their size, general appearance, and specific features as seen under the microscope.

As a general rule, the larger the adenoma, the more likely it is to eventually become a cancer. As a result, large polyps (larger than 5 millimeters, approximately 3/8 inch) are usually removed completely to prevent cancer and for microscopic examination to guide follow-up testing.

Malignant polyps — Polyps that contain cancerous cells are known as malignant polyps. The optimal treatment for malignant polyps depends upon the extent of the cancer (when examined with a microscope) and other individual factors. (See "Overview of colon polyps".)

COLON POLYP DIAGNOSIS — Polyps usually do not cause symptoms but may be detected during a colon cancer screening examination (such as flexible sigmoidoscopy or colonoscopy) (picture 1) or after a positive screening test for occult blood in the stool.

Colonoscopy is the best way to evaluate the colon for polyps because it allows the clinician to see the entire lining of the colon and remove most polyps that are found (occasionally, large polyps need to be removed during a separate procedure). During colonoscopy, a clinician inserts a very thin, flexible tube with a light source and small camera into the anus. The tube is advanced through the entire length of the large intestine (colon). (See "Patient education: Colonoscopy (Beyond the Basics)".)

The inside of the colon is a tube-like structure with a flat surface with curved folds. A polyp appears as a lump that protrudes into the inside of the colon (picture 1). The tissue covering a polyp may look the same as normal colon tissue, or there may be tissue changes ranging from subtle color changes to ulceration and bleeding. Some polyps are flat ("sessile") and others extend out on a stalk ("pedunculated").

Colonoscopy is the best test for the follow-up examination of polyps. Virtual colonoscopy using computed tomography technology is another test used to detect polyps.

COLON POLYP REMOVAL — Colorectal cancer is preventable if precancerous polyps (ie, adenomas) are detected and removed before they become malignant (cancerous). Over time, small polyps can change their structure and become cancerous. Polyps are usually removed when they are found on colonoscopy, which eliminates the chance for that polyp to become cancerous.

Procedure — The medical term for removing polyps is polypectomy. Most polypectomies can be performed through a colonoscope. Small polyps can be removed with an instrument that is inserted through the colonoscope and snips off small pieces of tissue. Larger polyps are usually removed by placing a noose, or snare, around the polyp base and burning through it with electric cautery (figure 2). The cautery also helps to stop bleeding after the polyp is removed.

Polyp removal is not painful because the lining of the colon does not have the ability to feel pain. In addition, a sedative medication is given before the colonoscopy to prevent pain caused by stretching of the colon. Rarely, a polyp will be too large to remove during colonoscopy, which means that a surgical procedure will be needed at a later time.

Complications — Polypectomy is safe although it has a few potential risks and complications. The most common complications are bleeding and perforation (creating a hole in the colon). Fortunately, this occurs infrequently (one in 1000 patients having colonoscopy). Bleeding can usually be controlled during colonoscopy by cauterizing (applying heat) to the bleeding site; surgery is sometimes required for perforation.

Medication use — Nonsteroidal anti-inflammatory drugs including aspirin, ibuprofen (sample brand names: Advil, Motrin), and naproxen (sample brand name: Aleve) can usually be continued before your colonoscopy. Acetaminophen (sample brand name: Tylenol) is safe to take. People who require anticlotting medications such as warfarin (sample brand name: Jantoven) should discuss how and when to stop and resume this medication with their clinician.

COLON CANCER PREVENTION

Follow-up colonoscopy — The results of the tissue analysis of polyps are discussed with patients when they are available, within a few weeks after the procedure, to decide if and when a follow-up examination is needed. People with adenomatous polyps have an increased risk of developing more polyps. There is a 25 to 30 percent chance that adenomas will be present on a repeat colonoscopy done three years after the initial polypectomy. Some of these polyps may have been present during the original examination but were too small to detect. Other new polyps may also have developed.

After polyps are removed, repeat colonoscopy is recommended. The exact time interval for follow-up varies depending upon several factors:

Microscopic characteristics of the polyp.

Number and size of the polyps.

Whether it was possible to examine the entire colon.

Ability to see the colon during the colonoscopy. A bowel preparation is needed before colonoscopy to remove all traces of feces (stool). If the bowel preparation was not adequate enough, feces may remain in the colon, making it more difficult to see small- to moderate-size polyps. In such situations, when the colonoscopy was not adequate, it should be repeated to ensure adequate visualization.

Screening saves lives. Persons who undergo regular screening for colon cancer are much less likely to die from colon cancer. Following the screening guidelines can also prevent people from developing colon cancer.

Lifestyle measures — Guidelines issued by one of the major medical societies in the United States (the American College of Gastroenterology) suggest the following:

Eat a diet that is low in fat and high in fruits, vegetables, and fiber

Maintain a normal body weight

Avoid smoking and excessive alcohol use

(See "Patient education: Diet and health (Beyond the Basics)" and "Patient education: Quitting smoking (Beyond the Basics)".)

IMPLICATIONS FOR THE FAMILY — First-degree relatives (a parent, brother, sister, or child) of a person who has been diagnosed with an adenomatous polyp or colorectal cancer before the age of 60 years, or those with two or more relatives with colorectal cancer at any age, have an increased risk of developing adenomatous polyps and colorectal cancer compared with the general population. Thus, a person diagnosed with an adenoma or colon cancer should share the information with family members, and each person should learn about the cancer history in their family. Some genetic conditions, such as Lynch syndrome, can also cause other cancers.

While screening for polyps and cancer is recommended for everyone (typically beginning at age 45), those at increased risk should begin screening earlier. The best test for screening in people with an increased risk of cancer is not known, although a sensitive test (such as colonoscopy) is usually recommended.

Relatives can be told the following, based on typical guidelines for screening people with a family history of colorectal cancer:

People who have one first-degree relative (biological parent, brother, sister, or child) with colorectal cancer or an advanced type of adenomatous polyp at a young age (before the age of 60 years), or two first-degree relatives diagnosed at any age, should begin screening for colon cancer earlier, typically at age 40, or 10 years younger than the earliest diagnosis in their family, whichever comes first. Screening usually involves colonoscopy, which should be repeated every five years. (See "Patient education: Screening for colorectal cancer (Beyond the Basics)", section on 'Average risk of colorectal cancer'.)

People with a second-degree relative (grandparent, aunt, or uncle) or third-degree relative (great-grandparent or cousin) with colorectal cancer should be screened for colon cancer similar to a person with an average risk. (See "Patient education: Screening for colorectal cancer (Beyond the Basics)", section on 'Average risk of colorectal cancer'.)

Some conditions, such as hereditary nonpolyposis colorectal cancer (Lynch syndrome), familial adenomatous polyposis, MUTYH-associated polyposis, and inflammatory bowel disease (eg, ulcerative colitis, Crohn disease) significantly increase the risk of colon polyps or cancer in family members. Colon cancer screening in this group is discussed separately. (See "Patient education: Screening for colorectal cancer (Beyond the Basics)", section on 'Increased risk of colorectal cancer'.)

WHERE TO GET MORE INFORMATION — Your health care provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Colon polyps (The Basics)
Patient education: Colon and rectal cancer (The Basics)
Patient education: Colonoscopy (The Basics)
Patient education: Colon and rectal cancer screening (The Basics)
Patient education: Acromegaly (The Basics)
Patient education: Familial adenomatous polyposis (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient education: Screening for colorectal cancer (Beyond the Basics)
Patient education: Colonoscopy (Beyond the Basics)
Patient education: Diet and health (Beyond the Basics)
Patient education: Quitting smoking (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Overview of colon polyps
Management and prevention of bleeding after colonoscopy with polypectomy
Clinical manifestations and diagnosis of familial adenomatous polyposis
Lynch syndrome (hereditary nonpolyposis colorectal cancer): Clinical manifestations and diagnosis
Colorectal cancer: Epidemiology, risk factors, and protective factors
Endoscopic removal of large colon polyps
Gardner syndrome
Peutz-Jeghers syndrome: Clinical manifestations, diagnosis, and management
Screening for colorectal cancer: Strategies in patients at average risk
Screening for colorectal cancer in patients with a family history of colorectal cancer or advanced polyp

The following organizations also provide reliable health information.

National Library of Medicine

(www.nlm.nih.gov/medlineplus/healthtopics.html)

The American Gastroenterological Association

(www.gastro.org)

The American College of Gastroenterology

(www.acg.gi.org)

The American Society of Colon and Rectal Surgeons

(www.fascrs.org)

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ACKNOWLEDGMENT — The editorial staff at UpToDate would like to acknowledge Robert H. Fletcher, MD, MSc, and Anne Charette, RN, MSN, ANP, who contributed to an earlier version of this topic review. The author, Dr. Doubeni, is a member of the US Preventive Services Task Force (USPSTF). This topic review does not necessarily represent the views and policies of the USPSTF.

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider's examination and assessment of a patient's specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms ©2023 UpToDate, Inc. and its affiliates and/or licensors. All rights reserved.
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