Which Colorectal Cancer Screening Option Is Right For You?
Updated: February 26, 2021
Colorectal cancer is a leading cause of cancer deaths nationwide. Yet it doesn’t have to be so deadly.
That’s because screening can find colorectal cancer before symptoms start—when it’s small, hasn’t spread, and is easiest to cure. Getting tested can even stop colorectal cancer from ever developing by letting doctors remove abnormal growths called polyps before they become cancerous.
Colorectal cancer is 90 percent beatable when caught early.
More colorectal cancer screening tests are available than ever before, so, which test is right for you? The answer may surprise you: “It’s the test you’re most comfortable with and consequently will stick with,” said gastroenterologist David Weinberg, MD, MSc, chair of the Department of Medicine at Fox Chase Cancer Center.
Here’s why: Colorectal cancer screening isn’t a one-and-done test. It has to be done regularly to be effective. What’s more, researchers are still trying to figure out which test is most effective. The best that can be said is that each of the available tests cuts your risk of dying from colorectal cancer by at least one-third, Weinberg said.
Still, each test has pros and cons. “And the test that makes the most sense for you might not seem right for someone else,” Weinberg emphasized.
Your options explained
Most people should start getting screened for colorectal cancer between ages 45-50. Don’t let this time pass by without talking to your doctor about when to begin screening and your choices for screening tests. Start the conversation sooner if you have a higher-than-average risk of colorectal cancer—for example, if you have a strong family history of the disease. You may need to start screening earlier.
In the meantime, to help you sort through your screening options, we sat down with Weinberg, who explained what the following tests involve.
- How it’s done: Your doctor uses a thin, flexible tube with a tiny video camera to view your entire colon and rectum. Your doctor will look for polyps and signs of cancer.
- How often: Every 10 years if results are normal.
- Advantages: A colonoscopy lets your doctor view your entire colon. If a polyp is found, it can be removed, which may keep the polyp from developing into a dangerous cancer.
- Disadvantages: You’ll need to clean out your bowels with strong laxatives and possibly a special diet a day or more before the test. Because you typically are given a sedative for the test, someone will also need to take you home afterward. And you may miss a day of work.
While a colonoscopy is usually a safe procedure, there’s about a 1 in 1000 risk that your bowel will tear during the test, plus a slight risk of bleeding or infection afterward.
Even though a colonoscopy is one of the most sensitive cancer screenings available, it—like any screening test—isn’t perfect. It may not detect all cancers nor all small or flat polyps.
- How it’s done: This test is done in a CT machine, scanning your abdomen to create a 3D image of your entire colon and rectum, in order to search for polyps and signs of cancer.
- How often: Every five years if results are normal.
- Advantages: This test finds both polyps and signs of cancer. And doctors can usually see your entire colon. It’s fairly quick, it doesn’t require sedation, and there aren’t any risks of serious complications like bowel tears. It may also be a good choice if you’re not a candidate for standard colonoscopy—for example, because you’re on blood thinners.
- Disadvantages: A CT scan uses x-rays, so you’re exposed to small amounts of potentially dangerous radiation. Like a standard colonoscopy, it can also miss some polyps. It also requires the same bowel cleanse prep. If something suspicious shows up on the scan, you’ll need a follow-up colonoscopy. And a virtual colonoscopy is not currently covered by Medicare nor all private insurance plans.
- How it’s done: This is performed in the same way as a colonoscopy—except your doctor examines only your rectum and the lower third of your colon.
- How often: Every five years if results are normal.
- Advantages: If your doctor finds one or more polyps, they can be removed, potentially preventing cancer. Typically, you don’t need sedation or a full bowel prep.
- Disadvantages: Any abnormalities in the upper parts of the colon—which is more than half of the colon—can’t be seen. As with a standard colonoscopy, there is also a very small risk of a bowel tear, infection, or bleeding.
Fecal occult blood test
- How it’s done: You use a test kit to take a stool sample. Then a lab tests the sample for tiny amounts of blood, which could be a sign of cancer or large polyps. There are two different types of this test. They differ slightly in how you prepare—some require you to go on a special diet—so make sure you read the kit’s instructions thoroughly.
- How often: Every year.
- Advantages: You can test yourself at home. So as long as you’re not squeamish about collecting your own stool sample, there’s no fuss. You don’t need to be sedated or take strong laxatives. And there’s no risk of complications.
- Disadvantages: These tests mainly find cancer—not polyps. They may also produce false alarms, since blood in stool can be triggered by hemorrhoids, ulcers, and other noncancerous conditions. And if a test is positive, you’ll need a colonoscopy.
Stool DNA test
- How it’s done: You also use a home test kit for this type of stool sample. The difference is that your stool is tested for DNA changes that may be signs of colorectal cancer or polyps. The available test kit in the U.S. checks for both DNA changes and blood.
- How often: Every three years.
- Advantages: This stool test is also convenient—there’s no prep at all—and has no risk of complications.
- Disadvantages: Like other stool tests, it mainly finds cancer—not polyps. It too can produce false positives. And abnormal results require a colonoscopy. Also, since it’s still fairly new, insurance may not pay for it (although Medicare does).
A leader in colorectal cancer screening
At Fox Chase, we do more than treat cancer. We also screen for the disease. A full range of traditional and advanced screening options are available.