According to the American Society of Colon and Rectal Surgeons, approximately 5% of the citizens are at risk of developing colon cancer in their lifetime. With the high incidence of colon cancer, the U.S. Preventive Task Force (USPTF) has recommended screening for the condition at regular intervals starting at the age of 50 and until 75. After 75, it is optional and individuals can stop once they are 80 years of age or above. This screening is more important for those who fall in the risk-prone age category. Screening has resulted in the reduction of a number of deaths in the last few years as colorectal polyps are removed before they can become malignant. A few of the screening methods recommended by USPTF are:

• High-sensitivity fecal occult blood tests (FOBT): This test checks for blood in feces that cannot be seen by the eye. Doing a test every 2 years after the age of 50 reduces the percentage of death by 33%. Even if no other screening test is done, the FOBT should be done annually.
• Stool DNA test: The only stool test approved by the FDA, this detects blood in the fecal matter and also detects DNA biomarkers in the three genes which come from the lining of the colon and the rectum. The software analyzes the blood and DNA biomarkers and gives results as positive or negative. Anyone who has tested positive will be recommended to undergo a colonoscopy to confirm cancer. This can be done every three years.
• Sigmoidoscopy: Inserted through the anus and rectum, the sigmoidoscope is a tube fitted with light and a lens along with a tool for removing sample tissue. Air or carbon dioxide is pumped to expand the lower colon and the rectum for a clear view. Any abnormal growth can be removed for biopsy. The colon has to be cleaned before the test and does not require sedation. This test can be done every five years and has reduced fatality rates by 60% to 70%.
• Standard colonoscopy:  A colonoscopy is carried out to examine the entire colon and some form of sedation is given to the patients during the procedure. The colon is completely cleaned before surgery. Doctors can also remove damaged or suspicious polyps to be used as samples for biopsy. This test has reduced fatalities by about 60% to 70%.
• Virtual colonoscopy: This screening method is the least invasive. It uses a CT scanner and takes a series of pictures of the colon and the rectum. Doctors then analyze these computerized pictures, to identify polyps and any other abnormalities. This process does not require sedation; however, the cleansing and expanding the colon is done for a good visual of the colon. If polyps are found, a standard colonoscopy is done to remove them.
• Double-contrast barium enema: This test is only used on those cases wherein a colonoscopy cannot be performed. The patient’s colon is cleaned after an enema with a barium solution. X-Rays then show the outline of the colon and rectum. It, however, cannot detect very small polyps.

Before and after colonoscopy, a patient may have to consume laxatives or have an enema to clean the colon. They must also consult the doctor about any of their current medications which might be changed if necessary.