Colorectal Cancer Prevention (PDQ®): Prevention - Patient Information [NCI]

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This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http://cancer.gov or call 1-800-4-CANCER

Colorectal Cancer Prevention

What is prevention?

Cancerprevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.

To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.

Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk, but it does not mean that you will not get cancer.

Different ways to prevent cancer are being studied, including:

  • Changing lifestyle or eating habits.
  • Avoiding things known to cause cancer.
  • Taking medicines to treat a precancerous condition or to keep cancer from starting.

General Information About Colorectal Cancer

Colorectal cancer is a disease in which malignant (cancer) cells form in the tissues of the colon or the rectum.

The colon is part of the body's digestive system. The digestive system removes and processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body. The digestive system is made up of the mouth, throat, esophagus, stomach, and the small and large intestines. The first 6 feet of the large intestine are called the large bowel or colon. The last 6 inches are the rectum and the anal canal. The anal canal ends at the anus (the opening of the large intestine to the outside of the body).
Gastrointestinal (digestive) system anatomy; shows esophagus, liver, stomach, colon, small intestine, rectum, and anus.
Anatomy of the lower digestive system, showing the colon and other organs.

Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer. Cancer that affects either of these organs may also be called colorectal cancer.

See the following PDQ summaries for more information about colorectal cancer:

  • Colorectal Cancer Screening
  • Colon Cancer Treatment
  • Rectal Cancer Treatment
  • Genetics of Colorectal Cancer

Colorectal cancer is the second leading cause of death from cancer in the United States.

The number of new colorectal cancer cases and the number of deaths from colorectal cancer are decreasing a little bit each year.

Finding and treating colorectal cancer early may prevent death from colorectal cancer. Screening tests may be used to help find colorectal cancer.

Colorectal Cancer Prevention

Avoiding risk factors and increasing protective factors may help prevent cancer.

Avoiding cancerrisk factors such as smoking, being overweight, and lack of exercise may help prevent certain cancers. Increasing protective factors such as quitting smoking, eating a healthy diet, and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.

The following risk factors may increase the risk of colorectal cancer:

Age

The risk of colorectal cancer begins to increase after age 40 and continues to increase as you get older.

Obesity and lack of exercise

Obesity is linked to an increased risk of colorectal cancer. A lifestyle that does not include regular exercise may also be linked to an increased risk of colorectal cancer.

Smoking

Smoking cigarettes is linked to an increased risk of developing colorectaladenomas (noncancerous tumors) and colorectal cancer. Cigarette smokers who have had surgery to remove colorectal adenomas have an increased risk for the adenomas to recur (come back).

Alcohol

Drinking alcoholic beverages may increase the risk of colorectal cancer.

The following protective factors may decrease the risk of colorectal cancer:

Hormone replacement therapy

Studies have shown that hormone replacement therapy (HRT) that includes both estrogen and progesterone lowers the risk of colorectal cancer in postmenopausal women. HRT with estrogen alone does not lower the risk. However, hormone use may increase the risk of breast cancer, heart disease, and blood clots.

Polyp removal

Most colorectal polyps are adenomas, which may develop into cancer. The removal of polyps in the colon and rectum may lower the risk of colorectal cancer. Bleeding and infection sometimes occur after polyps are removed during colonoscopy or sigmoidoscopy.

Colon polyps; shows two polyps (one flat and one pedunculated) inside the colon. Inset shows photo of a pedunculated polyp.
Polyps in the colon. Some polyps have a stalk and others do not. Inset shows a photo of a polyp with a stalk.

The effect of the following factors on the risk of colorectal cancer is not known:

Nonsteroidal anti-inflammatory drugs (NSAIDs)

It is not known if the use of nonsteroidal anti-inflammatory drugs (such as aspirin, ibuprofen, and naproxen) lowers the risk of colorectal cancer. Studies have shown that nonsteroidal anti-inflammatorydrugs (NSAIDs) lower the risk of colorectal adenomas (noncancerous tumors), but it is not clear if this results in a lower risk of cancerous tumors in the colon and rectum. The use of NSAIDs increases the risk of heart attack and stroke and some can cause bleeding in the stomach and intestines.

Vitamins

It is not known if taking vitamin D or high doses of folic acid lowers the risk of colorectal cancer.

Diet

It is not known if a diet low in fat and high in fiber, fruits, and vegetables lowers the risk of colorectal cancer.

Some studies have shown that a diet high in fat, proteins, calories, and meat increases the risk of colorectal cancer, but other studies have not.

For more information on diet and health, see the Fruits and Veggies website.

Statins

Studies have not shown that taking statins (cholesterol-lowering drugs) affects the risk of colorectal cancer.

Cancer prevention clinical trials are used to study ways to prevent cancer.

Cancer prevention clinical trials are used to study ways to lower the risk of developing certain types of cancer. Some cancer prevention trials are conducted with healthy people who have not had cancer but who have an increased risk for cancer. Other prevention trials are conducted with people who have had cancer and are trying to prevent another cancer of the same type or to lower their chance of developing a new type of cancer. Other trials are done with healthy volunteers who are not known to have any risk factors for cancer.

The purpose of some cancer prevention clinical trials is to find out whether actions people take can prevent cancer. These may include exercising more or quitting smoking or taking certain medicines, vitamins, minerals, or food supplements.

New ways to prevent colorectal cancer are being studied in clinical trials.

Clinical trials are taking place in many parts of the country. Information about clinical trials can be found in the Clinical Trials section of the NCI Web site. Check NCI's PDQ Cancer Clinical Trials Registry for colon cancer prevention trials or rectal cancer prevention trials that are now accepting patients.

Get More Information From NCI

CALL 1-800-4-CANCER

For more information, U.S. residents may call the National Cancer Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 9:00 a.m. to 4:30 p.m. A trained Cancer Information Specialist is available to answer your questions.

CHAT ONLINE

The NCI's LiveHelp® online chat service provides Internet users with the ability to chat online with an Information Specialist. The service is available from 9:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. Information Specialists can help Internet users find information on NCI Web sites and answer questions about cancer.

WRITE TO US

For more information from the NCI, please write to this address:

NCI Public Inquiries Office
Suite 3036A
6116 Executive Boulevard, MSC8322
Bethesda, MD 20892-8322

SEARCH THE NCI WEB SITE

The NCI Web site provides online access to information on cancer, clinical trials, and other Web sites and organizations that offer support and resources for cancer patients and their families. For a quick search, use the search box in the upper right corner of each Web page. The results for a wide range of search terms will include a list of "Best Bets," editorially chosen Web pages that are most closely related to the search term entered.

There are also many other places to get materials and information about cancer treatment and services. Hospitals in your area may have information about local and regional agencies that have information on finances, getting to and from treatment, receiving care at home, and dealing with problems related to cancer treatment.

FIND PUBLICATIONS

The NCI has booklets and other materials for patients, health professionals, and the public. These publications discuss types of cancer, methods of cancer treatment, coping with cancer, and clinical trials. Some publications provide information on tests for cancer, cancer causes and prevention, cancer statistics, and NCI research activities. NCI materials on these and other topics may be ordered online or printed directly from the NCI Publications Locator. These materials can also be ordered by telephone from the Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237).

Changes to This Summary (05 / 07 / 2009)

The PDQcancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

Editorial changes were made to this summary.

Questions or Comments About This Summary

If you have questions or comments about this summary, please send them to Cancer.gov through the Web site's Contact Form. We can respond only to email messages written in English.

About PDQ

PDQ IS A COMPREHENSIVE CANCER DATABASE AVAILABLE ON NCI'S WEB SITE.

PDQ is the National Cancer Institute's (NCI's) comprehensive cancer information database. Most of the information contained in PDQ is available online at NCI's Web site. PDQ is provided as a service of the NCI. The NCI is part of the National Institutes of Health, the federal government's focal point for biomedical research.

PDQ CONTAINS CANCER INFORMATION SUMMARIES.

The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries are available in two versions. The health professional versions provide detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions provide current and accurate cancer information.

THE PDQ CANCER INFORMATION SUMMARIES ARE DEVELOPED BY CANCER EXPERTS AND REVIEWED REGULARLY.

Editorial Boards made up of experts in oncology and related specialties are responsible for writing and maintaining the cancer information summaries. The summaries are reviewed regularly and changes are made as new information becomes available. The date on each summary ("Date Last Modified") indicates the time of the most recent change.

PDQ ALSO CONTAINS INFORMATION ON CLINICAL TRIALS.

A clinical trial is a study to answer a scientific question, such as whether a certain drug or nutrient can prevent cancer. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients and those who are at risk for cancer. During prevention clinical trials, information is collected about the effects of a new prevention method and how well it works. If a clinical trial shows that a new method is better than one currently being used, the new method may become "standard." People who are at high risk for a certain type of cancer may want to think about taking part in a clinical trial.

Listings of clinical trials are included in PDQ and are available online at NCI's Web site. Descriptions of the trials are available in health professional and patient versions. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237).

Date Last Modified: 2009-05-07


If you want to know more about cancer and how it is treated, or if you wish to know about clinical trials for your type of cancer, you can call the NCI's Cancer Information Service at 1-800-422-6237, toll free. A trained information specialist can talk with you and answer your questions.


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