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Table of Contents What is prevention?
General Information About Colorectal Cancer
Colorectal Cancer Prevention
Get More Information From NCI
Changes to This Summary (06/25/2007)
Questions or Comments About This Summary
About PDQ
What is prevention?
Cancer prevention 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.
Back to Top General Information About Colorectal Cancer
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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).
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| 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.
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. See the PDQ summary on Screening for Colorectal Cancer for more information.
Back to Top Colorectal Cancer Prevention
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Avoiding risk factors and increasing protective factors may
help prevent colorectal cancer.
Most people with a certain risk factor for cancer do not
actually get the disease. Doctors cannot always explain why one person gets
cancer and another does not. Talk to your doctor or other health care professional about cancer prevention methods that might help you.
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 colorectal adenomas (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.
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| 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-inflammatory drugs (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.
Back to Top 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. Deaf and hard-of-hearing callers with TTY equipment may call 1-800-332-8615. The call is free and 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 our “Best Bets” search box in the upper right hand corner of each Web page. The results that are most closely related to your search term will be listed as Best Bets at the top of the list of search results.
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), TTY at 1-800-332-8615.
Back to Top Changes to This Summary (06/25/2007)
The PDQ cancer 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.
Back to Top 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.
Back to Top 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); TTY at 1-800-332-8615.
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