Cologaurd. Anyone talk to their physician about using this product or have actually used it? Do tell.
Not sure if it was that brand, but yes. What do you want to know?
My doctor wants me to have another colonoscopy next year (it will have been 10 years since the last one, squeaky clean by the way). I’m hoping to persuade him to allow this instead.
I did a home fecal occult blood test, but it looks like Cologuard ™ is a DNA test of some kind.
The link is just an advert. And not a very good one either. Tells you virtually nothing about the product. How it works? What’s involved in taking it? What it does, etc, etc.
Talk about useless advertising!
I invested a little money in the company’s stock, so I know a little bit about it.
As hogarth says, it’s not a test for fecal blood, like the old fit test. It is a poop test that you do at home, and it specifically looks for the DNA signature which indicates you have polyps in your colon. If the test comes back positive, then you do have to go in for the colonoscopy procedure so the polyps can be removed. If the test is negative, then you’re done. No prep day of drinking the nasty stuff, no procedure, and no puncture risk. A lot of insurance companies are coming on board to cover it, as it’s way less expensive than a colonoscopy.
I plan to ask for it next time I’m due, which is in about four years now.
levdrakon, do physicians see this product a a substitute for getting a colonoscopy?
Not so much a substitute as a pre-screen to see if a colonoscopy is needed. I was due for a post 50 colonoscopy but this test came back negative so I don’t have to deal with the hassle of a colonoscopy which pretty much ruins your whole day.
“…which pretty much ruins your whole day.”
Agreed levdrakon. Please remember me on 12/30. (OOOH! OUCH! AH-YEE! YIKES! YEOWEY! …)
I’m not certain which is worse:
Americans will do anything to prevent having a doctor stick something in their ass.
(PSA was a disaster, now this, which looks to be away to say “YEA! no colonoscopy for ME!”)
PSA was developed as a way to track changes in a Prostate Cancer patient - it is all but completely useless in screening the undiagnosed.
Prostate cancers are usually very slow growing, so screwing up a diagnoses is not a life-and-death issue.
How about colorectal cancers? If this test proves as useless as PSA, how dangerous is a false negative? If we know that (whatever this test for) is present in colon cancers, can we be certain that it will ALWAYS be present-in-enough-concentration-to-trip-this-test?
If you can have massive cancers and still not trip this test, this test is worse than no test - it will give the patient the “news” that he/she is disease free.
Yes, I’ve had a colonoscopy - it is not fun, but we’re talking about real, grown-up diseases - not a pollen test to prevent itchy, runny eyes.
They already (seem to) know the accuracy of the Cologuard test: false negatives up to 8% of the time, false positives up to 13% of the time. The false positives aren’t so much of a problem, if the end result is you getting a colonoscopy anyway. The false negatives are more problematical, which is why I would expect to take it every 2 or 3 years instead of every 5 or 10 years. Cologuard is, I believe, designed for those at low risk or who, like me, have had a completely clean colonoscopy within the past 10 years.
I don’t see much point in comparing this to PSA tests. There is ample evidence that PSA tests are a very poor screening method, but there really isn’t anything else except a biopsy which is very invasive and potentially dangerous. Apparently there is a new, better test on the horizon but it doesn’t seem to be approved yet.
While the OP did not ask about the validity of Cologuard as a screening method for colorectal cancer, now that it has come up it seems to be quite viable but not the end-all that eliminates the need for colonoscopies.
eta: I too have had a colonoscopy, and it far less unpleasant than the prostate biopsy I have also had. But still if I can avoid the prep, I will.
I’ve had two of them. I cannot imagine what the heck you two are talking about.
Drink some tolerable-tasting drinks one afternoon, poop a few times, then tomorrow visit a clinic and sleep on a gurney for an hour, then spend the rest of the day lazing about on the Dope while feeling mildly opiated. BFD.
“Ouch” is the one thought I’ve never had in the context of a colonoscopy.
Color me utterly baffled at this line of thinking. Not picking specifically on either person in the quote above; they’re far from the only people to express this attitude in any number of these threads.
Getting drugged and laying around all day is ruining my whole day.
Well, my last colonoscopy used different meds than my first. I was mostly awake throughout, and distinctly remember screaming at one point because it hurt like a bitch. Apparently the tube did not want to go around some corner. (I’m going to posit I was just drugged enough to remove my screaming inhibition. I made it through childbirth without doing it, and this wasn’t that bad.) OTOH, the prep has changed and was much easier this time. Colon cancer runs in my family, so it’s not like I’m skipping this ever. It’s just not always as easy as it was for you.
I’ve had five, and the prep drinks have always been the worst part of the experience for me, but are indeed (barely) “tolerable” considering the worst alternative. Having watched my father die of colon cancer (sitting by his side during his final ten hours), I’ll gladly endure any testing that might spare me the same fate. I agree- BFD.
But as someone just upthread already pointed out, mileages can vary.
A reasonable coverage of the issues. And a NYT bit too.
From the latter, the test:
Um, no. You missed 58% of the precancerous polyps. That is not reliably detecting them.
It’s biggest sales pitch seems to be increasing screening in those who would otherwise refuse colonoscopy.
FWIW to me a screening test should trade a high false positive rate for an extremely low false negative rate. The idea for a screen is to not miss any even if some still need to get the more accurate test. Colorguard missed 8% of the cancers and 58% of potentially precancerous polyps. To me that is a huge fail as a screening test.
The longer established FIT test - annual fecal immunochemical test - may the better route for someone at routine risk unable to handle a bowel prep or for who having someone to drive them home afterwards is not an option or who for whatever reason will not do the test. Maybe this done every three years will have acceptable numbers. Maybe not. We don’t yet know. If paying out of pocket the FIT done annually is by far the most cost-effective for the routine risk population.
I’ll stick with colonoscopy for myself, prep and all. For now anyway. I’m at low risk, had one at 50 and not due until I hit the ten-year anniversary in almost three years.
And anyone at higher risk, such as family history or past history of polyps, who does Colorguard, is, IMHO, making a very poor choice.
This. My mother died from colon cancer. The only way I could be at higher risk is if I actually had it myself. Until both the gastroenterology and oncology communities agree a new procedure is bulletproof, I’ll stick with the colonoscopy.
As an exercise I calculated out the positive predictive values (PPV) for this test for the two broadly defined populations of 50 to 64 years old (annual incidence of colon cancer about 70/100,000) and 65+ (annual incidence about 250/100,000). I think I did this right. Good old Bayes theorem.
PPV for Colorguard is about 0.0046% for the 50 to 64 year old group. IOW a positive result is likely to be falsely positive 210 to 220 more often than to be a true positive. While negative result is very very likely to be a true negative, given having cancer it will falsely tell you you do not have cancer 8% of the time.
The PPV for the 65+ group is 0.0178% which translates to a test being a false positive only about 56 times as often as being a true positive. And it will again miss 8% of the cancers which now is a four times larger number each time.
No idea how far down the missed positives would go following the company’s suggested repeat every three years suggestion … any guesses would require making extremely huge assumptions … but only considering the cancer positive calls alone leading to having the colonoscopy anyway and given a Colorguard 13% false positive rate then by year nine (test at point zero, year 3, year 6, and year 9) a low risk person without cancer would have a 42% chance of having to have a colonoscopy anyway. And given that a test result + for potentially precancerous polyps would also lead to colonoscopy the odds are likely that a colonoscopy will occur anyway.
So if you do this as your approach don’t freak out when you get a positive and realize that the odds are more likely than not that you’ll end up with a colonoscopy within the ten year clean bill of health cycle anyway … and that those with cancer will be told they are clear 8% of the time each screening.
I agree with your logic, your attitude, and your math. For a screening test this seems to have a far too high a false negative rate. A clarifying question if I may …
AIUI the test tries to detect precancerous polyps. What is the conversion rate in untreated subjects from polyps to active cancer? A few percent, or substantially all? And on what timescale?
My point being your conclusion was
Bolding mine.
Is that valid or would it be more correct to say something like "anyway … and that those with a precancerous condition (or possible active cancer) will be told they are clear 8% of the time each screening. Or am I raising a distinction that ends up not being much of a clinical difference?
The latter part is easy.
No, that was the rate of those missed who had actual cancer on colonoscopy - 8%. Not precancerous conditions. The sensitivity for detecting advanced precancerous lesions (advanced adenomas or sessile serrated polyps measuring ≥1 cm in the greatest dimension) on colonoscopy was only 42.4% … IOW it missed 57.6% of them, more than half will be told they are clear and have advanced precancerous lesions. It detected 69.2% of polyps with high-grade dysplasia. (Missing 30.8% of them.) High-grade dysplasia is best considered carcinoma in-situ. The actual study is here.
Used as a one time test it caught more cancers and polyps than the fecal immunochemistry test (FIT) with more false positives as well. The FIT $25 and the intent is to do it annually (and the experts grant that as a possible alternative to colonoscopy in low risk populations with outcomes of life years saved done in that manner within 90% of the colonoscopy standard.) Colorguard is $600 and they are suggesting doing it every three years. Done every three years it may perform similarly to the FIT done annually … or may not.
The first question is a bit harder to answer because obviously it would be unethical to leave advanced lesions in place and see how long it takes. Still they have estimates. The time scale of conversion from advanced adenoma to cancer is considered to be 2 to 5 years with annual transition rates varying by age: “estimates of annual transition rates from 2.6% in the youngest age group to 5.6% in age group 80+ among women, and from 2.6% in the youngest age group to 5.1% in the oldest age group among men.”
Small adenomas may never advance at all or may become advanced adenomas and then cancers. If they go that path it is estimated to take about ten years on average. Hence the ten year interval after my clean scope seven years ago.