There have been several TV commercials about Cologuard®, a colon cancer screening test. The ad says Cologuard is easy to use, noninvasive and can be completed in the privacy of your own home. The test detects certain DNA markers and blood in stool, which are associated with the possibility of colon cancer or precancer. But should it be used in place of a traditional colonoscopy?
When detected early enough, colon cancer is preventable and treatable. Diagnosis in an early stage usually means a better prognosis and chance of survival. Colonoscopies are considered the gold standard because they can detect cancer and precancer.
During a colonoscopy, a provider looks for polyps, or growths. These growths may be removed during the procedure, so they don’t have the chance to develop into cancer. So why don’t people have a colonoscopy if it’s the gold standard?
Negative comments about colonoscopy preparation can make people reluctant to sign up. Stories about drinking gallons of an awful tasting liquid are daunting. But in recent years, the taste and amount of the liquid prep needed has improved.
It is also much easier to get a colonoscopy when the provider is part of an open access colonoscopy program. This allows healthy people to schedule a screening colonoscopy without the inconvenience of an initial office visit. Patients save both time and cost of an office co-payment. To qualify, you must be age 50 or older with an average risk for colon cancer.
Here are some of the pros and cons of a traditional colonoscopy.
- Gold standard for detection of all cancerous and precancerous lesions.
- Considered the best test for prevention of colorectal cancer and related deaths.
- The doctor can view the entire colon and rectum.
- Abnormal tissue, such as polyps, and tissue samples (biopsies) can be removed through the scope during the exam.
- Covered by Medicare and is less expensive than Cologuard every three years.
- Needed only every 10 years in average risk patients if no polyps are found on initial examination.
- Only acceptable test in symptomatic patients (e.g. Iron deficiency anemia, bleeding, change in bowel habits).
- Requires bowel preparation.
- Requires a provider and procedure appointment.
- Patient receives sedation.
- Very small risk of complication.
Cologuard doesn’t require any kind of preparation. There are no dietary or medication restrictions, no laxative preparation, no sedation and no time away from home or work. But there are some downsides to consider.
If you test positive with Cologuard (or any kind of stool-based screening method), you will need further evaluation. Most of the time, this means needing a diagnostic colonoscopy.
According to Cologuard’s website, the Cologuard test result should be interpreted with caution. A positive test result does not confirm the presence of cancer. Patients with a positive test result should be referred for diagnostic colonoscopy. A negative test result does not confirm the absence of cancer. Patients with a negative test result should discuss with their doctor when they need to be tested again.
False positives and false negative results can also occur. In a clinical study, 13% of people without cancer received a positive result (false positive). In that same study, 8% of people with cancer received a negative result (false negative).
Here are some of the pros and cons of using the at-home screening test Cologuard.
- No bowel preparation needed.
- Convenient, with no appointment or preparation needed.
- Covered by Medicare.
- May miss up to 8% of colorectal cancer.
- May miss up to 58% of advanced polyps.
- Has a 13% false positive rate, which increases with age.
- Required every 3 years, which may make it harder to remember or comply.
- Considered a 2nd tier test, offered only if a colonoscopy or annual FIT is refused.
Colon Cancer Prevention
Colon cancer has a 90% survival rate when detected in early stages. Any efforts to increase participation rates in cancer screenings should be supported, but not all screening is equal. While at-home tests offer convenience and lower cost, traditional colonoscopies are the gold standard for detection and prevention.
The American Cancer Society recommends that those 45 or older talk to their doctor about screening options. Also, talk with your insurance company about coverage. It’s important to get tested as often as recommended. No matter what your age, talk to your doctor about your family medical history. People at higher risk for colorectal cancer because of family history or certain health conditions might need to start screening earlier than age 45.
In addition to getting recommended screenings, a healthy diet, exercise and avoiding tobacco can help protect you from colon cancer.
Muhannad Heif, MD, is a board-certified gastroenterologist with ProMedica Physicians Digestive Healthcare. He is also the chief of Gastroenterology at ProMedica Toledo Hospital.
*This article is not an endorsement of Cologuard®, or other related products. This article is meant to provide general information related to colon health and potential treatment options. The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. To learn more about colon health and available treatment options, please consult your physician.