Some much-deserved props for the oft-forgotten fecal occult blood stool test for colon CA

We do a lot of colonoscopies in this country, looking for colon cancer. And that’s a good thing.

But do people realize that the only screening test for colon cancer shown by randomized controlled trials to decrease colon cancer mortality and incidence is fecal occult blood testing (FOBT)? It’s an inexpensive (about $20) at-home test kit that often seems to get lost in the enthusiasm for in-office higher-tech procedures like standard colonoscopy – or its new sibling, virtual colonoscopy.

This week, a study in Health Affairs reminds us about the relative benefits of FOBT. And it’s about time. Kaiser Permanente in California thinks highly enough about FOBT that it mails test kits to subscribers to use at home. From a public health perspective – trying to reach as many people as possible with a cost-effective approach – it sure seems to make sense.

Katie Hobson writes about this study on the Wall Street Journal health blog and includes links to the Health Affairs study and to a story, “Virtual Colonoscopy Misses Mark on Cost.” See Katie’s story and visit those links if you’re interested in learning more.

Meantime, one message for journalists is to include a discussion of FOBT whenever discussing colon cancer screening. It seems incomplete and imbalanced not to do so.

And a possible message for consumers (although we don’t give medical advice on this blog), ask your physician about FOBT whenever other colon cancer screening methods (e.g., colonoscopy, flexible sigmoidoscopy) are brought up.

Why NOT talk about the evidence for (or against) FOBT?


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dr parveen chopra

July 30, 2010 at 11:30 am

as usual quite a thought-provoking and useful post.

Dennis (Investigator/Negotiator) at Medical BillDog

July 30, 2010 at 11:49 am

Sorry if I’m being obtuse, but are you saying FOBT alone is adequate? If I buy one of these tests (what, at Walgreens?), can I then blow off the colonoscopy if I don’t get a positive on a FOBT?
If I do get a positive on the FOBT, do I go for a colonoscopy or just get a sigmoidoscopy? Or are there gradations?

Gary Schwitzer

July 30, 2010 at 3:30 pm

Thanks for your note.
You weren’t being obtuse. I hope that I don’t sound evasive with my answer.
But your question begs a response that is really medical advice and I don’t do that, shouldn’t do that and won’t do that.
I merely tried to point out some facts:
1. There is good evidence to support the use of FOBT tests.
2. Yet they’re often not used.
3. A new study this week highlighted some benefits.
But all screening tests – including all colon cancer screening tests – have flaws and limitations.
No advice. Just facts. Talk with your doctor if you have questions, but arm yourself with some of the facts going in. This blog can’t be an exhaustive compendium of information on a complex issue like colon cancer screening test choices. But it can heighten awareness on some under-appreciated issues – which I think this one is.

Dennis (Investigator/Negotiator) at Medical BillDog

July 30, 2010 at 6:26 pm

No, not evasive. You said “we don’t give medical advice in this blog.”
Still, between what you said here and what I dug up elsewhere on the Internet, looks to me like I should be able to obtain a FOBT (preferably a Fecal Immunochemical Test) OTC, administer said test at home, and send it in for results. Do I need a doctor’s scrip to purchase a FOBT? If the results show blood in my stool, I’ll need to get a more visual test done.
In some ways, it sounds sort of counterintuitive, though. What if I have blood in my stool and it turns out it’s from diverticulitis? I thought you were supposed to eschew shoving cameras through the sigmoid in cases of diverticulitis. Could cause micro-ruptures around the infected diverticula, n’est-ce pas? Can a reading of a FOBT (FIT or otherwise) differentiate between infection and tumors of other origins?

dr parveen chopra

July 30, 2010 at 7:26 pm

Though i am not an expert in the field, still i can suggest that if anybody gets FOBT positive, he definitely needs to talk to his doctor. Then, further line of investigation is decided. But surely, a positive FOBT needs further work-up.
Even if FOBT is negative, it should definitely be brought into the notice of one’s doctor when one is with him for periodic health check-up.
Indeed articles like this at heighten public awareness about under-appreciated issues.


August 1, 2010 at 7:04 am

I need to point out that the only way that the fecal occult blood test saves anyone’s life is if there is a follow-up colonoscopy. It is actually the DIAGNOSTIC colonoscopy that removes the polyps and prevents the cancer. Can it be inferred from this that colonoscopy saves lives? I think it can, if used in concert with FOBT.
The recommendations we follow are as such:
1. Starting at age 50 all low-risk people get yearly FOBT.
2. A positive test is followed by a colonoscopy.
3. A negative test is followed by a sigmoidoscopy UNLESS a person has had a negative colonoscopy in the past 10 years or a negative sigmoidoscopy in the past 5 years.
4. People who have had a negative colonoscopy do not get FOBT for the following 2 years, as a positive test wouldn’t be again followed by a colonoscopy until then.
This seems to work for most people, and we have gotten our compliance level fairly high using reminders for both doctors and patients.

Dennis (Investigator/Negotiator) at Medical BillDog

August 1, 2010 at 11:44 am

Doc Rob to the rescue. Hey, I just keep running into you everywhere, Doc. If you moved to Austin, I’d be proud to list you as my PCP. Your flowchart is pretty much what I expected until you hit step 3. If my FOBT is negative (again, I’m assuming FIT), why do I need a sigmo? What do you expect to see that the FOBT wouldn’t have caught? I understand that the sigmoid colon is The Usual Suspect as far as polyps and colorectal cancer are concerned, but we were talking about someone in the not-at-risk group to begin, right?
So, I’m a healthy patient with no gastrointestinal problems, no weight problems, no family history of cancer, and I come in with a negative FOBT. I’ve never had a colonoscopy. You tell me to get a sigmoidoscopy. I ask, why? Why do I need to give up solid food for a day and allow someone to stick a probe ten inches (12?) up my ass? What’s your answer?

Kate Murphy

August 2, 2010 at 9:26 am

The Health Affairs article was really looking at screening large groups of people in the most cost-effective way. The reality is that we do not have either sufficient numbers of gastroenterologists or the funds to screen all average risk people with colonoscopy.
Fecal occult blood testing is an effective and cost-effective way of getting more people screened and saving more lives.
Colonoscopy can be prioritized for those who have a positive fecal occult blood test or those who are at high risk for colon or rectal cancer.

Dennis (Investigator/Negotiator) at Medical BillDog

August 3, 2010 at 4:05 pm

Yeah, Kate, sure. So, positive FOBT gets a colonoscopy. Makes perfect sense. That still doesn’t explain why a negative FOBT needs a sigmoidoscopy.