Colorectal Cancer Screening

Screening refers to testing that is done before symptoms develop. Screening for colorectal cancer allows your doctor to detect cancer early, when it is highly curable. Some screening tests, including colonoscopy, also help prevent cancer by allowing the detection and removal of growths, called polyps, some of which can become cancerous over time.

Experts believe that most colorectal cancers start as a polyp. Over time, some types of polyps—such as an adenoma or adenomatous polyp—can turn into cancer. Detecting and removing a precancerous polyp can help prevent colorectal cancer.

In addition, when found early, colorectal cancer is highly curable. Colorectal polyps and early cancers often cause no symptoms, which is why screening is important.

Most colorectal cancers occur in people age 50 and older, but the disease is being increasingly diagnosed in younger people. Colorectal cancer affects both men and women and people of all ethnic backgrounds. About 70 percent of colorectal cancers develop in people who have no family history of the condition.

People who are at average risk for colon cancer—meaning they have no risk factors—need to begin screening at age 45.

The U.S. Multi-Society Task Force on Colorectal Cancer Screening recommends that people at average risk have one of these first-line colorectal cancer screening options:

• colonoscopy every 10 years
• fecal immunochemical test with high sensitivity for cancer every year

Other screening options for people at average risk for colorectal cancer may include one of the following:

• CT colonography every 5 years
• FIT-fecal DNA test every 3 years
• flexible sigmoidoscopy every 5 to 10 years

People who have certain risk factors should start screening at a younger age with colonoscopy. These risk factors include having a personal or family history of colorectal polyps or colorectal cancer; a personal or family history of a genetic colorectal cancer syndrome; or a personal history of inflammatory bowel disease.

Doctors recommend that people with a family history of advanced polyps, called adenomas, or colorectal cancer get initial colonoscopy screening 10 years before the age that the youngest affected relative was diagnosed, or age 40, whichever is earlier.

Our doctors can help you determine when you should start getting screened, and can recommend an appropriate screening approach for you. Some of the most commonly recommended screening tests include the following:

A colonoscopy is the most comprehensive screening test for colon cancer. For men and women at average risk, it is recommended every 10 years, starting at age 45.

Colonoscopy allows for the examination of the entire colon and rectum. It also enables the doctor to detect and remove precancerous polyps immediately. This means a colonoscopy can be used to both prevent and to detect colorectal cancer.

Right before your colonoscopy, most people receive an intravenous sedative that causes them to become relaxed or fall asleep during the procedure. During the colonoscopy, your gastroenterologist—a doctor who specializes in screening for, diagnosing, and treating conditions of the gastrointestinal tract—threads a narrow, flexible tube called a colonoscope into the rectum and through the entire colon, or large intestine. The colonoscope has a small camera at its end that allows the doctor to view and examine the lining of the colon and rectum.

The doctor can identify and remove polyps using a wire loop with an electric current, which is placed through the colonoscope. He or she can also take samples, or biopsies, of suspicious growths or tissue in the colon and rectum. Polyps and other growths are sent to a pathologist, who examines the tissue under a microscope.

Based on your test results and your risk factors, your gastroenterologist can tell you when you need another colonoscopy or, if necessary, recommend further treatment. If you are at average risk for colorectal cancer and your colonoscopy is normal, your next colonoscopy is most likely in 10 years.

Because of the medication used to relax you during the procedure, someone needs to escort you home afterward.

Preparation

Before a colonoscopy, your doctor provides you with instructions for a bowel preparation—often called “the prep”—that helps to clean out the colon and rectum before the procedure.

Most bowel preps involve consuming a clear liquid diet and taking a laxative regimen by mouth, starting the day before the procedure. It is important to complete the bowel prep to ensure that your colon and rectum are clean. This helps the doctor to detect any polyps or early cancers during the procedure.

Improving Detection of Polyps and Early Cancers

Colonoscopy is a highly effective test, and NYU Langone gastroenterologists are dedicated to studying and offering the latest advances in technology to help make this procedure even more effective in detecting polyps and early cancers.

A new technology is cuff-assisted colonoscopy, or Endocuff, which involves the use of a disposable device that fits on the end of a colonoscope. The device resembles a tiny hairbrush, with soft, flexible, finger-like projections. These projections allow doctors to flatten folds on the wall of the colon and rectum, potentially improving their ability to find polyps located behind these folds.

Another technology being studied by NYU Langone gastroenterologists is balloon-assisted colonoscopy. This technique involves using a colonoscope with a balloon fitted onto its tip. The balloon is inflated to help doctors flatten the folds of the colon and rectum, potentially making polyps easier to spot and remove.

Other Advances in Colonoscopy Screening

Other advances that may be used along with a screening colonoscopy include capsule endoscopy, which is also called capsule colonoscopy. A capsule endoscopy may be used to view the parts of the colon that were not examined during colonoscopy.

The test involves swallowing a camera about the size of a vitamin that takes pictures on its way through the digestive system. These images are transmitted to a data recorder and are downloaded for viewing by the doctor.

In addition, our gastroenterologists offer a same-day, non-oral colon irrigation option for people who cannot tolerate the bowel prep drink before a colonoscopy. While the traditional bowel prep drink is started the day before a colonoscopy, the colon irrigation prep takes about 45 minutes and is done the same day as your procedure.

A fecal immunochemical test, also known as a FIT test or FIT kit, is a stool test. It detects blood in the stool but does not require that you avoid any medications or foods beforehand.

Most FIT tests are considered more sensitive than other types of home testing kits for occult, or hidden blood in the stool. As with those tests, a stool sample is collected at home and sent to a laboratory for analysis.

Many different FIT tests are available; only those done as a take-home kit and those having a high sensitivity for cancer should be used for colorectal cancer screening. This test is used primarily to help detect colorectal cancer, and does not prevent cancer.

If the FIT test is recommended by your doctor as part of your screening plan, it needs to be repeated every year. If the results indicate that there is blood in the stool, a follow-up colonoscopy is required to determine the source of the bleeding.

A FIT-fecal DNA test, or multitarget DNA stool test, called Cologuard, looks for both blood and DNA, or genetic material, shed by cancerous tumors and some polyps in the stool.

This test does not require you to stop any medications or avoid certain foods. It is done as a take-home kit, in which a stool sample is collected and mailed to the laboratory for analysis.

This test is highly sensitive for detecting cancers but is not as sensitive for finding polyps. It is performed every three years. If the test results are abnormal, a follow-up colonoscopy is required to examine the colon and rectum.

If your doctor detects an abnormality on any of these colon cancer screening tests, a follow-up colonoscopy is required. In addition, if you have certain risk factors—such as a family history of colon polyps or cancer or a personal history of inflammatory bowel disease—you need to be screened by colonoscopy.