Colorectal Cancer Prevention
Key Points for This Section
- Avoiding risk factors and increasing protective factors may help prevent cancer.
- The following risk factors increase the risk of colorectal cancer:
- The following protective factors decrease the risk of colorectal cancer:
- The effect of the following factors on the risk of colorectal cancer is not known:
- Taking medicine to reduce cholesterol levels does not affect the risk of colorectal cancer.
- Cancer prevention clinical trials are used to study ways to prevent cancer.
- New ways to prevent colorectal cancer are being studied in clinical trials.
Avoiding cancer risk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. 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.
Having a parent, brother, sister, or child with colorectal cancer doubles a person's risk of colorectal cancer.
Cigarette smoking is linked to an increased risk of colorectal cancer and death from colorectal cancer.
Smoking cigarettes is also linked to an increased risk of forming colorectal adenomas. Cigarette smokers who have had surgery to remove colorectal adenomas are at an increased risk for the adenomas to recur (come back).
Obesity is linked to an increased risk of colorectal cancer and death from colorectal cancer.
A lifestyle that includes regular physical activity is linked to a decreased risk of colorectal cancer.
Taking aspirin every day for at least 5 years decreases the risk of colorectal cancer and the risk of death from colorectal cancer. In a study of women, taking aspirin every other day for 10 years decreased the risk of colorectal cancer.
Studies have shown that combination hormone replacement therapy (HRT) that includes both estrogen and progesterone lowers the risk of invasive colorectal cancer in postmenopausal women. However, combination HRT does not lower the risk of dying from colorectal cancer.
Not all hormone replacement therapy decreases the risk of having colorectal cancer. HRT with estrogen alone does not lower the risk of having invasive colorectal cancer or the risk of dying from colorectal cancer.
The possible harms of hormone replacement therapy include an increased risk of having:
Most colorectal polyps are adenomas, which may develop into cancer. Removing colorectal polyps that are larger than 1 centimeter (cm) may lower the risk of colorectal cancer. It is not known if removing smaller polyps lowers the risk of colorectal cancer.
Studies have shown that taking the nonsteroidal anti-inflammatory drug celecoxib reduces the risk of colorectal adenomas (benign tumors) coming back after they have been removed. It is not clear if this results in a lower risk of cancerous tumors in the colon and rectum. Taking celecoxib also has been shown to reduce the number of polyps that form in the colon and rectum of patients with familial adenomatous polyposis (FAP).
The possible harms of NSAIDs include:
- Kidney problems.
- Bleeding in the stomach, intestines, or brain.
- Heart problems such as heart attack and congestive heart failure.
For more information on diet and health, see the Nutrition for Everyone: Fruits and Vegetables Web site.
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.
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 list of cancer clinical trials for colon cancer prevention trials or rectal cancer prevention trials that are now accepting patients.