Are Home Screenings an Accurate Way to Detect Colorectal Cancer?


There have recently been media reports about patients having to pay a medical co-payment bill from a colonoscopy performed after receiving a positive Cologuard® test. Below are a few links to the report in various media.


An issue not featured in the article is that many of these home testing outcomes may be false-positive, causing people to worry about having polyps or cancer and being charged a possible medical co-payment even when their colonoscopy outcomes are negative.

A recent investigation involving 450 individuals presented at Digestive Disease Week in May 2021 found that merely two percent of individuals who received a positive stool test had cancer of the colon. And, two-thirds of the individuals received a false-positive outcome, which may have generated further personal costs for a diagnostic colonoscopy to confirm the outcomes of the home test, as explained by the news reports. Alternatively, many insurance policies may provide benefits for a simple colonoscopy that identifies and minimizes the risk of colorectal cancer as a preventive procedure.

About colorectal cancer

Colorectal cancer, or cancer of the large intestine, results in the death of more than 50,000 individuals every year. It's the second most prevalent cause of death due to cancer among people in the United States. Colorectal cancer can be prevented, treated, and overcome — but only with accurate and early detection. Since this type of cancer commonly begins as polyps (growths in the colon), finding and excising such polyps is the optimal way to reduce the risk of colorectal cancer. There are three forms of testing used to perform screenings for colorectal cancer:

  1. Fecal Immunochemical Test (FIT) – 30% of large colon polyps are identified
  2. Stool DNA (Cologuard tests) – 42% of large colon polyps are detected
  3. Colonoscopy – 95% of large colon polyps are found

It is important to note that colonoscopy is still the gold standard for identifying polyps. Polyps discovered during a colonoscopy are removed during the procedure, often reducing the need for further treatments.

Potential polyps detected through a Cologuard or positive FIT test necessitate a colonoscopy to excise the polyps. Bigger colorectal growths may go undetected with FIT and Cologuard tests. In the event that these growths fail to be discovered and removed, the possibility of developing colon cancer increases.

Recently, the U.S. Preventive Services Task Force (USPSTF) advised that screenings for colorectal cancer begin at age 45 instead of 50. As a result, an additional 22 million adults between the ages of 45 – 49 need to be screened for colon cancer within this year alone. Even though home testing kits might seem like an easier, cost-effective choice, it is worth noting that a colonoscopy is the only screening process that can identify and curtail the development of colon and rectal cancer.

Identifying vs. preventing colon cancer

Cologuard is intended to identify cancerous indicators (including DNA) in the fecal sample collected. However, in 58% of cases, concerning premalignant polyps aren't detected at all with Cologuard. A Cologuard test is considered a screening test and should be repeated every three years if the starting screening outcome provides a negative result. Cologuard has a reputation of providing a substantial number of false-positive and false-negative outcomes. According to a recent survey, two out of three of the individuals who completed the Cologuard at-home test received false-positive results. Positive test outcomes following a blood or fecal test require a colonoscopy to confirm the findings. Because the fecal or blood test is deemed to be the "screening" test, the follow-up colonoscopy is regarded as the "diagnostic" colonoscopy.

A colonoscopy exam is conducted to diagnose and reduce the risk of colorectal cancer. This procedure identifies over 95% of dangerous, premalignant intestinal polyps and removes these growths during the process. Colonoscopies also allow doctors to capture a specimen of tissue for pathology testing to specify more accurately if colorectal cancer is prevailing. Given these circumstances, colonoscopy procedures are significantly more definitive and present preventive measures since they remove any precancerous polyps discovered in the large intestine.

The main categories of colonoscopy procedures include:

Screening/preventive colonoscopies are performed commonly for adults with no current or past gastric concerns who are age 45 or older and wish to establish baseline data to learn if they are at risk for colorectal cancer. A screening colonoscopy exam permits the physician to visualize any abnormal tissues in the large intestine, like abnormal cells and polyps. At the time of a preventive colonoscopy, polyps (which can turn cancerous) can be taken out and biopsies can be performed to learn if whether malignant tissue is occurring in the colon. A screening colonoscopy is recommended every ten years for asymptomatic patients between the ages of 45 – 75 who have no personal or family history of gastrointestinal diseases, colon polyps, or colon cancer. Many insurance plans frequently provide benefits for screening colonoscopies for preventive reasons. It is advisable to consult with the insurance provider prior to having any procedure to review coverage and estimate any personal costs surrounding this exam under the patient's plan.

Surveillance colonoscopies are conducted if a patient has a history of GI disease, colon polyps, or cancer but may be asymptomatic (no GI symptoms in the present or past). The need for a surveillance colonoscopy may vary depending on the individual's personal history. Patients who have experienced colon polyps in the past would undergo a surveillance colonoscopy and likely have further surveillance evaluations at shortened intervals every 2 – 5 years or so. It is essential to check with the insurance company before undergoing any exam to ascertain coverage limits and any estimated out-of-pocket costs surrounding this type of procedure.

Follow-up/diagnostic colonoscopies are performed if a person exhibits or has previously experienced a GI diagnosis or disease, GI symptoms, polyps, or anemias. A person's medical history and findings from any earlier colonoscopy procedure(s) guide the recommendation for a diagnostic colonoscopy. For instance, if a patient takes a non-intrusive colon cancer screening test, such as Cologuard or FIT, that generates any kind of positive result, a diagnostic/follow-up colonoscopy would be required to verify the findings of the screening test. Follow-up colonoscopy procedures commonly produce out-of-pocket expenses. Therefore, it is prudent to speak with the insurance carrier prior to undergoing any service to review coverage limitations and learn of any potential out-of-pocket costs for this service under the patient's policy.

People who are 45 or older should undergo a screening for colon cancer to garner baseline data and to serve as a preventive measure that fosters long-term colon health. It is essential to understand the differences between colon cancer screening procedures and how each type works. Colonoscopy is still the greatest form of diagnosing cancer and the only form of colon cancer prevention available today.

Find out more about colorectal cancer screenings in DFW

Regular colon cancer screenings are simple examinations that can safeguard lives. Our board-certified gastroenterologists proudly serve patients throughout the DFW area and are here to provide the assistance you need for long-term GI health. To learn more about colorectal cancer home screenings or to schedule a colonoscopy, reach out to Texas Digestive Disease Consultants today.