Cologuard

Poop in a Bucket!

Cologuard

Pam Popper, President
Wellness Forum Health

[ DYI's Disclaimer:  This is NOT medical advice; I am NOT a doctor nor do I have any formal medical education of any kind.  However, I do find information that you may find interesting for your own personal investigation and/or doctor. ]

Cologuard is the first stool test to use a person’s DNA rather than blood to screen for colon cancer. It was approved by the FDA in 2014, and is currently included in the American Cancer Society’s colon cancer screening guidelines. The product is made by Exact Sciences, is available by prescription only and costs $599. Many insurance plans pay 100% of the cost for this test.

According to the company’s website, "Cologuard is not for everyone and is not a replacement for diagnostic surveillance colonoscopy or surveillance colonoscopy in high-risk individuals. False positives and false negatives do occur. Any positive test result should be followed by a diagnostic colonoscopy. Following a negative result, patient should continue participating in a screening program with a method appropriate for the individual patient. Cologuard performance when used for repeat testing has not been evaluated or established.[1]

The test is embraced by medical professionals and offered by institutions like Mayo Clinic. "Cologuard represents a significant advancement in identifying colorectal cancer at its most treatable stage. We believe offering this new tool will promote patient and community public health and may move more patients to get screened earlier — a critical step in beating this prevalent and preventable cancer," according to Vijay Shah, M.D., chair of Mayo Clinic gastroenterology and hepatology.[2]

It seems, however, that enthusiasm about this test may be premature and most likely unwarranted. The company acknowledges that the test results in false positives and false negatives. In the trial submitted to the FDA for approval, 13% of people were incorrectly diagnosed as potentially having cancerous polyps. This is considerably higher than the 5% error rate for blood-based stool tests.

A concerning factor is the recommendation to have a colonoscopy in response to a positive test, and the need for those with negative test results to continue testing with some other method. What exactly is the value of this test then? Experts provide some interesting answers to this question. Dr. Joel Lavine, chief of gastroenterology at Columbia University Medical Center, says that false positives "could be concerning," but the concerns can be addressed with "more definitive colonoscopy tests."

Dr. Bennett Roth, professor of gastroenterology at UCLA says that the biggest benefit from the test is that it can encourage more people to have a colonoscopy, which he refers to as the gold standard for diagnosing colon cancer. He says "It doesn’t replace the need for a colonoscopy." Kevin Conroy, CEO of Exact Sciences, agrees, and states that the company’s goal is to "increase the screening pool" of people who have colonoscopy.[3]

So to summarize, the test is expensive - $599 as compared to $25 for a blood stool test – 

AND 

its main purpose is to herd more people into having a colonoscopy, 

which is encouraged whether the test results are negative or positive.

This is interesting since an increasing number of people are looking for alternatives to colonoscopy both because it is invasive and involves some risk, and because it is not an effective population screening tool.

The Canadian Task Force on Preventive Health Care (CTFPHC) updated its recommendations for colon cancer screening 2016, stating that - 

it "does not recommend using colonoscopy as a primary screening test for colorectal cancer due to lack of evidence."[4] 

In fact, not one randomized controlled trial shows that colonoscopy reduces the risk of dying of colon cancer.[5] 

Serious complications occur in 5 out of every 1000 procedures, and perforation occurs in 1 per 1000 procedures. Most important, however, is that 1250 people have to have a colonoscopy in order to save one life, and for every life saved, one person is harmed or dies from a complication of the procedure.[6]  

The recommendation of useless tests like Cologuard in order to generate more prospects for more useless testing does not improve public health; it just drives up costs, which are already extraordinary.

The FIT test is a much more effective alternative. It is a home stool test that requires no liquids to clean out the colon, no sedatives or anesthesia, and almost no risk.  It is effective in diagnosing almost 79% of colorectal cancers. One meta-analysis of 19 studies showed that FIT detects almost 4 in 5 cancers with a single test. The researchers concluded "[T]his systematic review and meta-analysis suggests that FITs have high accuracy, high specificity, and moderately high sensitivity for detection of CRC."[7]

My recommendation for Cologuard is to just say "no."

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[1] https://www.cologuardtest.com/?gclid=EAIaIQobChMI-sOOqv2l3AIVHbjACh3M-QJNEAAYASAAEgKWDPD_BwE

[2] https://bringmethenews.com/news/mayo-clinic-first-to-offer-at-home-colonoscopy-alternative

[3] David Lazarus. "A good alternative to having a colonoscopy? Maybe not." Los Angeles Times August 21 2014.

[4] http://canadiantaskforce.ca/ctfphc-guidelines/2015-colorectal-cancer/ accessed 2.24.2016

[5] Baxter N, Goldwasser M, Paszat L, Saskin R, Urbach D, Rabeneck L. "Association of colonoscopy and
death from colorectal cancer." 

Ann Intern Med 2009 Jan 6;150(1):1-8

[6] Levin T, Zhao W, Conell C et al. "Complications of colonoscopy in an integrated health care delivery system."  

Ann Intern Med 2006 Dec 19;145(12):880-886
Richardson A. "Screening and the number needed to treat." 

J Med Screen 2001;8(3):125-127

[7] Lee J, Liles E, Bent S, Levin T, Corley D. "Accuracy of Fecal Immunochemical Tests for Colorectal Cancer: Systematic Review and Meta-analysis." 

Ann Intern Med. 2014;160(3):171-181-181.