Colorectal cancer is a condition that causes abnormal cells to develop in either the colon or rectum. The colon is an area of the digestive system located near the middle portion of the large intestine and the rectum is just below the colon at the end of the large intestine. When abnormal cancer cells start to grow in the colon or rectum, they can accumulate into masses known as tumors. Tumors can prevent normal cells from receiving the blood and other nutrients required to keep the body healthy, but if the cells are discovered before they multiply and form masses, they have a higher likelihood of being treatable. Colorectal cancer screening is the process of a doctor examining the colon and rectum on a regular basis to look for any cell changes and treat them before they grow into tumors.
Doctors generally recommend colorectal cancer screening for all individuals over the age of 50, as they are more likely to develop the condition. People younger than age 50 who have other risk factors, such as a family history of colorectal cancer or who have other conditions affecting the digestive tract, may also be screened. One of the most noninvasive types of screening is a fecal occult blood test, in which a doctor examines a portion of a patient’s feces to check for any hidden blood by covering the feces in a chemical that becomes blue in the presence of blood. If blood is detected in the feces, it is a possible sign of colorectal cancer or other digestive tract disorders, so a doctor may recommend additional testing.
Another common type of colorectal cancer screening is a colonoscopy, a procedure in which a doctor uses a long, narrow instrument known as a colonoscope to look at the inside of the colon and rectum. A colonscope is inserted into the body through the rectum and contains a light and small camera that allows the doctor to get a close look at any cell changes. Patients may need to be sedated before the procedure. If any cells in the colon or rectum look suspicious, a doctor will typically remove small samples and test them for cancer.
A double contrast barium edema is a type of colorectal cancer screening that lets doctors examine the entire colon and rectum, similar to a colonoscopy, but does not require patients to be sedated beforehand. A liquid solution containing barium sulfate, a chemical that allows areas to show up on X-rays, is inserted into a patient’s rectum. A doctor then performs X-rays on the colon and rectum to look for any abnormal cell growths that may require further testing. Unlike a colonoscopy, samples of abnormal cells cannot be collected during the screening, so another appointment for physically removing the cells for testing will usually be required.