Inflammation Marker Might Signal Colon Cancer Risk

[wdlove]

C-Reactive Protein Tied To Heart Disease

CHICAGO -- A new study finds that high blood levels of a protein linked to heart attacks might also be an early warning sign of colon cancer.


http://www.thebostonchannel.com/health/2815503/detail.html?treets=bos&tml=bos_health&ts=T&tmi=bos_health_1_12150102042004

 

[arn]

possibly interesting... but no one is sure what to do with that information.

arn

 

[wdlove]

I hope that this blood test will lead to early detection of colon cancer. Along with the MRI. That it would lead to a decrease need for the colonoscopy, eventually end the use.

 

[arn]

Originally posted by wdlove
I hope that this blood test will lead to early detection of colon cancer. Along with the MRI. That it would lead to a decrease need for the colonoscopy, eventually end the use.

I'm not sure if that'll happen... there's something to be said about direct visualization as well as biopsies.

Even if MRI managed to become a diagnostic tool for colon cancer (which it is not at the moment... probably because it would miss many of them) then colonoscopy would be the next step to get a biopsy.

The problem with any simple blood test to try to detect anything is the question of false positives and false negatives.

A positive CRP may mean that someone has 2x the risk of colon cancer.... but what if that just means it's .02% instead of .01%?

How many unnecessary colonoscopies are people going to get? And how many people are you going to hurt (via complications) when they don't actually have color cancer.

arn

 

[blaster_boy]

I'd rather have a blood test than a colonoscopy ANY time.

A relative of mine had to undergo those a few times - not funny. At all.

 

[arn]

Originally posted by blaster_boy
I'd rather have a blood test than a colonoscopy ANY time.

A relative of mine had to undergo those a few times - not funny. At all.

perhaps... but getting a "positive" blood test just means that you are twice as likely to have colon cancer than someone with a "negative" test.

So, what's that? .02% instead of .01%? (I made these numbers up, for an example)

What do you do if your "colon cancer blood test" is positive? Do you go get a colonoscopy?

That means for every 10,000 people with a positive test... only 2 people actually have colon cancer. If you gave everyone with a POSITIVE blood test a colonoscopy.... that means 9,998 people would get unnecessary colonoscopies.

And with a rate of adverse events for colonoscopy being something like 1 in 1000... that means you've just seriously hurt 10 people (amongst this 10,000)

obviously, these arn't the acutal numbers... but just shows that the blood test isn't necessarily of great use by itself.

arn

 

[wdlove]

The sad thing is that the colonoscopy also misses polyps that may be precancerous. It is my understanding that the MRI actually catches more of these polyps, although it also is not 100%. Hopefully with further testing the effectiveness will increase.

 

[arn]

Originally posted by wdlove
The sad thing is that the colonoscopy also misses polyps that may be precancerous. It is my understanding that the MRI actually catches more of these polyps, although it also is not 100%. Hopefully with further testing the effectiveness will increase.

From my understanding MRI is inferior to colonoscopy if you're talking about colon cancer detection. If anything it would catch less of the smaller polyps.

You may be thinking about "virtual colonoscopies" which involve a ct machine... but it is worse at detecting smaller polyps.

http://www.medicinenet.com/Colon_Cancer_Screening/page2.htm

- Virtual colonoscopy cannot find small polyps (less than 5 mm in size) that are easily seen at colonoscopy.

- Virtual colonoscopy is not as accurate as colonoscopy at finding flat_cancers or premalignant lesions that are not protruding, that is, are not polyp-like.

- Small pieces of stool can look like polyps on virtual colonoscopy and lead to a diagnosis of polyps when there are none.

- Virtual colonoscopy cannot remove polyps. Thirty to forty percent of people have colon polyps. If polyps are found by virtual colonoscopy, then colonoscopy must be done to remove the polyps, and, therefore, many individuals having virtual colonoscopy will have to undergo a second procedure, colonoscopy.

- There have not been studies to compare the discomfort levels of colonoscopy versus virtual colonoscopy, and comparisons will be difficult to do. The discomfort of colonoscopy is from the insertion of the colonoscope and air insufflation. The discomfort of virtual colonoscopy is from air insufflations. Patients' perceptions of discomfort from both procedures are highly variable. What makes the discomfort difficult to compare is that patients undergoing colonoscopy usually are sedated intravenously, while patients undergoing virtual colonoscopy are not sedated. As a result, patients may actually find colonoscopy more comfortable than virtual colonoscopy. On the other hand, sedation increases the risk of complications from colonoscopy.