No doubt you’ve heard about the value of screening in reducing deaths from colon and rectal cancer (colorectal cancer, or CRC), the fourth most common cancer diagnosis in the U.S. Screening is the process of looking for cancer in people who do not have symptoms. The idea is that screening catches cancers early, when they’re more treatable.
Screening is particularly effective for CRC, in part because it’s a slow-growing cancer. Colon cancer doesn’t develop overnight, says Dr. Alok Khorana, director of the gastrointestinal malignancies program at the Cleveland Clinic. It’s a process of transformation from a normal colon to polyps (growths on the colon wall) to cancer and can take several years. If you find polyps at a pre-cancerous stage, you can remove them so they never become cancer.
[See: 8 Questions to Ask Your Doctor About Colon Cancer.]
Who Should Be Screened?
The United States Preventive Services Task Force, an independent panel of health experts, strongly recommends colon cancer screening for adults ages 50 to 75 who are at average risk for developing colon cancer. Adults 76 and older should talk to their doctor about whether to continue screening, taking into consideration their overall health and prior screening history.
Individuals who are at high risk should start screening earlier. “If you have a family history of colon cancer, you should start screening at an age that’s 10 years earlier than the youngest person in your family had cancer,” Khorana says.
Types of Screening Tests
There are several colon cancer screening tests. They differ on how easy they are to administer and how frequently you should repeat them. Medicare and most insurance plans cover CRC screening (check with your plan for specific coverage).
Some tests are good at detecting things, and some tests are good at both detecting and preventing colon cancer, says Dr. David Greenwald, director of clinical gastroenterology and endoscopy at Mount Sinai Hospital in New York. A colonoscopy, for example, allows you to look for cancer and to remove polyps at the same time, making it a preventive procedure as well as a screening test. Other tests detect abnormalities, but require additional follow up.
Visual examination. A colonoscopy and flexible sigmoidoscopy both use a flexible lighted tube to view the inside of the colon. The flexible sigmoidoscopy examines the rectum and lower portion of the colon (the sigmoid colon). It doesn’t find cancers in the upper colon. A colonoscopy examines the entire length of the colon. Both the sigmoidoscopy and colonoscopy require prep work to clean your bowels thoroughly before the procedure. A colonoscopy requires sedation, so you need someone to drive you home afterward.
Virtual colonoscopies use high-resolution CT scans to see inside the colon. It’s less invasive; however, you must still cleanse your bowel prior to the procedure. If your doctor finds polyps, you will then need to undergo a traditional colonoscopy to remove them.
[See: 10 Seemingly Innocent Symptoms You Shouldn’t Ignore.]
Stool tests. Fecal occult blood tests and fecal immunochemical testing, or FIT, both look for blood in the stool, which may be a sign of cancer. “The FOBT is an effective test, but it has to be done consistently, every couple of years,” says Khorana. “It has a high rate of false positives [detects blood due to something other than cancer] and false negatives [cancer is present but is not bleeding].”
“The FIT is more sensitive,” Greenwald says.
A newer test, the FIT-DNA, detects blood in the stool and identifies genetic mutations that are associated with CRC. “The downside [of the FIT-DNA] is that the mutations tend to occur later in the cancer [so it may not help find cancer early] or the cancer may not have these mutations,” Khorana says.
Stool tests are easy to administer; you simply provide a stool sample to a lab or your doctor’s office. If you have a positive result, you’ll need a follow-up colonoscopy.
Which Test Is Right for Me?
“The colonoscopy is the gold standard for CRC testing,” Khorana says. “It’s the test most [medical] organizations advocate for.”
Unfortunately, there are barriers to screening, Greenwald says, including fear, embarrassment and logistical challenges (for example, taking time off work to undergo a colonoscopy), and each test has pros and cons. Talk to your health care provider about which test is right for you, and don’t be embarrassed, he says. “The best test is the one that gets done.”
[See: 6 Options for People Who Don’t Want a Colonoscopy.]
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Should You Be Screened for Colon Cancer? originally appeared on usnews.com
