The possible harms of polyp removal during colonoscopy or sigmoidoscopy include a tear in the wall of the colon and bleeding.
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) other than aspirin
It is not known if the use of nonsteroidal anti-inflammatory drugs or NSAIDs (such as celecoxib, naproxen, and ibuprofen) 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:
It is not known if a diet low in fat and meat 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—More Matters" Web site.
It is not known if taking vitamin D or high doses of folic acid lowers the risk of colorectal cancer.
It is not known if taking calcium supplements lowers the risk of colorectal cancer.
Taking medicine to reduce cholesterol levels does not affect the risk of colorectal cancer.
Studies have shown that taking statins (cholesterol -lowering drugs) does not increase or decrease 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.