Consider all your options for colorectal cancer screening: newer, sophisticated tests can help prevent colon cancer, but be sure to consider their limitations along with their advantages.
"Studies have shown that certain populations don't want to come in for a colonoscopy," says Carol A. Burke, MD, Vice Chair of Cleveland Clinic's Department of Gastroenterology & Hepatology and Director of the Center for Colon Polyp and Cancer Prevention. "The best test, of course, is the one that gets done."
SEARCHING FOR BLOOD IN THE STOOL
Tests for blood in your stool are the most basic way to detect bleeding from colorectal cancer or polyps. In the guaiac-based fecal occult blood test (g-FOBT), using a kit from your doctor, you provide three stool samples and return the kit to your physician's office or a lab for testing.
The g-FOBT can reduce deaths from colorectal cancer, but it can't tell the origin of blood in the stool or if the blood is from colorectal cancer or polyps. Vitamin C supplements, nonsteroidal anti-inflammatory drugs (aspirin, Advil[R], Aleve[R] and Motrin[R] are examples), as well as certain fruits, vegetables or blood from undercooked meat, can alter the test results.
Another home stool test, the fecal immunochemical test (FIT), requires one or two stool samples and specifically identifies blood from the colon, not from elsewhere in the intestinal tract. FIT is unaffected by foods, so patients undergoing the test do not have to follow the dietary restrictions associated with the g-FOBT, Dr. Burke says.
"The fecal immunochemical test is sensitive to pick up not only colon cancer but also colon polyps," Dr. Burke says. "And we know that patients have preferred FIT testing because adherence has been shown to be better."
ENTER STOOL DNA
One of the newest additions to the screening lineup is stool DNA testing. The Cologuard[R] stool DNA test is done at home and includes a FIT test and molecular testing for DNA changes indicative of colorectal cancer or polyps. A 2014 study found the DNA-test was better than a FIT test alone at identifying colorectal cancers and precancerous polyps. However, the rate of false-positive results in the study was higher with the DNA test compared to the FIT. And, Dr. Burke cautions that while stool DNA testing is approved by Medicare every three years, the ideal screening interval remains in question.
She also points out that while most insurance providers cover annual colorectal cancer screening with g-FOBT or FIT, with stool DNA testing Medicare and other insurers will fund screening only every three years. "So, if you have the DNA test done and it's negative and in a couple years you want to have a colonoscopy, co-insurance or co-pays may be in effect," Dr. Burke says.
A VIEW OF THE COLON
Like colonoscopy, other tests allow your doctor to visually inspect the colon. Among them is flexible sigmoidoscopy (flex sig), an endoscopic exam of the rectum and left side of the colon. Studies have found it may reduce the incidence and death rate from colorectal cancer. However, research suggests that certain populations, such as African-Americans, do not benefit from flex sig to the degree that Caucasians do, Dr. Burke explains.
In capsule endoscopy, marketed as PillCam Colon[R], you swallow a large capsule containing a camera that takes thousands of pictures of your digestive tract. The camera transmits these images to a device you wear on your belt.
On the plus side, capsule endoscopy does not require sedation. However, insurance coverage is generally lacking, Dr. Burke says, and, compared to colonoscopy, the procedure requires a more extensive bowel preparation.
For patients unable to undergo optical colonoscopy, Dr. Burke recommends computed tomography (CT) colonography, or "virtual colonoscopy," which creates a threedimensional view of the colon and rectum. CT colonography is non-invasive and does not require sedation, but patients still must complete a full bowel preparation and inflation of the colon with air.
Research suggests that CT colonography is about as effective as optical colonoscopy at detecting larger polyps, but it may be more likely to miss smaller ones. "CT colonography would be appropriate for patients who had an incomplete colonoscopy," Dr. Burke says. "We need to choose the screening measure that patients will undertake."
COLONOSCOPY: STILL THE STANDARD
Keep in mind that suspicious findings found on any of these screening tests warrant a colonoscopy to confirm the presence of polyps or cancer, or to remove polyps.
Despite newer, less invasive screening methods, colonoscopy remains the preferred choice for colorectal cancer screening, Dr. Burke says. Today's colonoscopies are less burdensome, with lower-volume bowel preparations and better techniques that lessen discomfort and increase the quality and efficacy of the procedure, she explains.
"Often, just having a conversation with your doctor can allay your fears about having a colonoscopy," Dr. Burke says. "For healthy, average-risk individuals, the best choice is still a high-quality colonoscopy."
Consider your health
When weighing a decision about colorectal cancer screening, ask your doctor if you're healthy enough to benefit from screening. Some experts recommend against routine colorectal cancer screening in average-risk adults over age 85; however, more so than your age, your health, life expectancy and screening history should factor into your decision.
ACG guidelines for colon cancer screening
The American College of Gastroenterology recommends these screening options and intervals for adults age 50 and older at average risk of colorectal cancer:
Prevention tests (should be offered first)
* Colonoscopy every 10 years (preferred option)
* Flexible sigmoidoscopy every 5-10 years * ([dagger])
* CT colonography every 5 years * ([dagger])
(for patients who decline prevention tests)
* Annual fecal immunochemical test ([dagger]) (preferred option)
*Annual high-sensitivity guaiac-based fecal occult blood test * ([dagger])
* Stool DNA test (interval uncertain) * ([dagger])
* Alternative options
([dagger]) A follow-up colonoscopy is needed if any one of these tests returns a positive result.
Consider your health
When weighing a decision about colorectal cancer screening ask your doctor if you're healthy enough to benefit from screening. Some experts recommend against routine colorectal cancer screening in average-risk adults over age 85; however, more so than your age, your health, life expectancy and screening history should factor into your decision.
COLORECTAL CANCER SCREENING OPTIONS AT A GLANCE METHOD BENEFITS Colonoscopy "Gold standard" screening tool; finds polyps/can-cer throughout entire colon; can remove polyps Flexible sigmoidoscopy Finds/removes polyps/cancer in rectum and distal colon; may not require full bowel prep or sedation CT colonography Non-invasive test that can view entire colon; quick and safe; no sedation needed Capsule endoscopy Provides view of entire colon and digestive tract; fairly safe; no sedation needed Guaiac-based fecal Safe; no bowel prep or sedation; performed occult blood test at home; inexpensive Fecal immunochemical Safe, no bowel prep or sedation; done at test(FIT) home; no dietary restrictions; can identify cancer and polyps Stool DNA test Safe; no bowel prep or sedation; done at home; no dietary restrictions; can identify cancer and polyps METHOD POTENTIAL DRAWBACKS Colonoscopy Requires full bowel preparation; small risk of bowel injury Flexible sigmoidoscopy Views only a third of colon; small risk of bowel injury; requires enema prep; colonoscopy needed if abnormalities found CT colonography Full bowel prep needed; potential for false-positives; insurance coverage lacking; colonoscopy needed if abnormalities found Capsule endoscopy More extensive bowel prep; insurance coverage lacking; colonoscopy needed if abnormalities found Guaiac-based fecal Less accurate than other tests; dietary occult blood test restrictions needed; colonoscopy needed if abnormalities found Fecal immunochemical Potential for false-positive results; test(FIT) colonoscopy needed if abnormalities found Stool DNA test Potential for false-positive results; more expensive; colonoscopy needed if abnormalities found
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|Publication:||Men's Health Advisor|
|Date:||Apr 1, 2016|
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