Colorectal cancer is the third most commonly diagnosed cancer, and cause of death from cancer, in the United States. According to a recent study by the American Cancer Society, the rate of colorectal cancers, located in the colon or rectum, is on the rise for people under 50. But despite that trend, experts project almost 60 percent of new diagnoses in 2017 will be for those 65 years old and up.
March is National Colon Cancer Awareness Month. A good time to remember that colorectal cancer can be prevented by detecting precancerous polyps, which are small, abnormal growths in the colon. Polyps can be removed during a colonoscopy. Many people have no symptoms of early colorectal cancer. Screenings are important because they can detect cancer at an early, curable stage. Studies show a lower death rate from colorectal cancer among people who get screened compared to those who do not.
You have several screening options — the most effective one is the one you will follow through with.
Fecal Screening Tests
Fecal screening tests can find tiny amounts of blood in stool that can either be a sign of large polyps or cancer. Your health care provider will determine if you need this screening every year or every two years. You can take these types of tests at home with a kit and instructions from your doctor’s office. If your results are positive, you will need to follow up with a colonoscopy.
Colonoscopy
Many studies show the rate of cancer death is 68 to 88 percent lower for people who have a colonoscopy compared to those who do not. This is because experts can remove polyps during the colonoscopy, before polyps can become cancerous. A polyp is considered a pre-cancerous lesion. Removing them is a primary prevention strategy. This screening can also detect cancer in an early, curable stage.
CT Colonography
A CT Colonography is a procedure using imaging or x-rays to produce a detailed image of the colon and rectum. A CT Colonography can be effective in detecting raised polyps. However, this type of screening is not as good as a colonoscopy for detecting flat polyps, which are harder to recognize. Also, with CT Colonography, if a polyp is discovered it cannot be removed right then. You will need a colonoscopy to remove the polyp.
Blood-Based Tests
The Food and Drug Administration recently approved a blood-based colorectal cancer screening test. However, more studies are needed to evaluate the long-term benefit of this screening tool. The U.S. Preventive Services Task Force recommends you start getting screened when you turn 50 if you are at average risk for colorectal cancer. The guidelines suggest a stool test annually or every three years, or a colonoscopy every 10 years, or a CT Colonography every five years. If you are between 76 and 85 years old, talk to your doctor about the risks and benefits of screening. You should stop screening after 85 years of age.
The task force recommends earlier and more frequent screening if you’re high risk. If you have a direct relative diagnosed with colorectal cancer before 60 years of age, you should have a colonoscopy when you turn 40, or when you’re 10 years younger than the relative’s age when they were diagnosed. Whichever is earlier.
There is no “best” strategy for colorectal cancer screening. The best test to screen for colon cancer is the test you can complete consistently.
Naeem Newman, MD, is a surgical oncologist at AAMC Surgical Oncology.
