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Commentary: Colonoscopy vs. Cologuard – ‘gold standard’ still shines
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Naresh T. Gunaratnam, MD, a gastroenterologist and research director at Huron Gastroenterology in Ypsilanti, Michigan , provided data for Cologuard’s initial validation study. In this guest commentary, Gunaratnam discusses that while the colorectal cancer screening tool is an appropriate choice when a patient refuses a colonoscopy, the way in which Cologuard is being marketed presents concerns for gastroenterologists.
Cologuard is an excellent choice and it works well for its original intentions. In fact, Thomas F. Imperiale, MD, and colleagues published a study in the New England Journal of Medicine in 2014 that clearly demonstrated that Cologuard is a step up from, or equivalent to, fecal immunochemical tests (FIT).
It’s obviously helping to increase the available tools we have for colon cancer screening. However, there is growing concern among gastroenterologists that the direct-to-consumer marketing of the product is overstating its role in helping to solve a serious public health problem.
Colonoscopy remains the gold standard for CRC screening. When Imperiale and colleagues did their study, the results clearly demonstrated that Cologuard was inferior to colonoscopy. Cologuard missed one out of every 13 people who had cancer detected by screening colonoscopy.
But when there’s a really spritzy public health campaign with a cartoonish box appearing in advertisements, the average consumer will likely say, “I want to have that done, because it seems so easy.” When a consumer sees this on television, or listens to NPR and hears this, or see celebrities endorse this, they think, “I need to get a colon cancer screening, and this seems like a very simple way.”
What the individual loses in that message is that Cologuard should not be the primary way to screen for colon cancer, but rather should be considered a secondary option.
Convenience not the most important factor
From a practical point of view, Cologuard is easy to use. If you’re a patient, you might think, “I don’t want to do the prep, I don’t want to take a day off, I don’t want to get a colonoscopy” because there’s this perceived inconvenience factor.
If a consumer feels they are getting something equivalent, and the ads are suggesting that Cologuard is easier to do, then it makes sense that consumers will choose the easier option.
On the other side, primary care physicians (PCPs) are measured on whether they meet various quality metrics. One of those metrics is colorectal cancer screening. Ordering a colonoscopy and waiting for the results takes time. Primary care doctors can meet that quality metric by ordering a Cologuard, making it easier for them to fulfill their quality metrics.
When I read articles that question whether Cologuard can replace screening colonoscopy, or when Exact Sciences executives say that health care providers should be obligated to offer Cologuard, this concerns me, and other gastroenterologists as well.
As physicians, we need to better delineate the options to our patients, and make sure they understand that convenience should only be one of the factors included in their decision-making. We must make sure patients have enough information to base their decisions on what science says is the best screening option.
What physicians should say
Science says that colonoscopy is the gold standard for colorectal cancer screening. Patients should also know that The Multi-Society Task Force on Colorectal Cancer recommends Cologuard as an acceptable second-line screening option, but that physicians should recommend colonoscopy first.
MSTF ranked colonoscopy in the top-tier of screening tests because it is the only test that detects colorectal cancer and prevents it by removing polyps during the procedure. It is the only test that is appropriate for people who have risk factors such as a personal or family history of colorectal cancer or polyps.
What physicians should tell their patients is, “Colonoscopy is what the medical societies recommend as the first-line screening option, but if you choose not to get a colonoscopy, then Cologuard is an appropriate choice.” Our concern is that this nuance is not being conveyed through the marketing.
Patients also need to understand that while Cologuard is convenient, it will fulfill the screening benefit covered for most patients via insurance. If the Cologuard is positive, the patient will need a follow-up colonoscopy as recommended. Then, the follow up colonoscopy will be considered a therapeutic procedure and may come with a high insurance co-payment. With 45% of positive Cologuard tests being false positive, there are a lot of patients who may have to pay excessive copays and other costs that they wouldn’t have faced if screening colonoscopy was their first screening test of choice.
Considering the screening intervals
Cologuard is recommended once every 3 years. If a person is considered average-risk and that person has a negative colonoscopy, their next colonoscopy might not be for another 10 years. So, a person has 10 years of “protection,” which for a day off from work, is a pretty good deal.
Most patients may not know that most colon cancers start off as polyps. According to the NEJM study, Cologuard missed 30% of higher-risk precancerous lesions, including high-grade dysplasia. It missed almost 60% of advanced precancerous lesions.
According to the American Cancer Society, about one-third to one-half of all individuals will eventually develop one or more adenomas. Although only 10% are estimated to progress to invasive cancer, all adenomas have the potential to become cancerous – and they account for approximately 96% of all colorectal cancers.
If you know that removing polyps prevents cancer, and that benefit only comes from having a colonoscopy, then why not get a colonoscopy? When viewed this way, patients might think that one day of inconvenience to prevent colorectal cancer is a good deal. Ultimately, we need to help our patients choose the screening test that’s right for them. But, we must provide them with enough information to make an informed decision.
When Cologuard is not appropriate
I had a patient who came to me because of a positive Cologuard. She previously had a colonoscopy and we found several polyps during the procedure. She was then scheduled to have a repeat colonoscopy in 5 years.
This year we sent her a reminder letter that her colonoscopy was due. She told me that she took that letter to her primary care doctor and the physician said she didn’t need the colonoscopy if she screened with Cologuard because it was the same thing.
The patient was prescribed Cologuard, which was positive. She came to our practice for her follow up colonoscopy. Before the procedure, I spoke with her and heard that her primary care doctor said Cologuard and colonoscopy would have the same result.
Cologuard is inappropriate as a follow-up test for someone who is at higher risk for colon cancer. It is not approved for individuals at high risk of colorectal cancer, including those with conditions that increase risk, such as a personal history of polyps, chronic ulcerative colitis, Crohn’s disease, familial adenomatous polyposis, or a family history of colorectal cancer or polyps.
Now her required follow-up colonoscopy is considered a therapeutic test rather than a diagnostic screening test, and she is facing a higher copay.
As discussed previously here and elsewhere, the best screening test is the one that gets done. If someone chooses not to get a colonoscopy, and uses Cologuard, that is absolutely better than no screening at all.
However, it’s always better to prevent a cancer than to treat a cancer. If we truly want to prevent colorectal cancer, the best screening test is a colonoscopy.
References:
American Cancer Society, Colorectal Cancer Facts & Figures 2017-2019;
Disclosures: Gunaratnam reports no relevant financial disclosures as it relates to colon cancer screening.