- Great, great, so the question
is what about Vitamin D, calcium.
No one's looked at that in IBD.
I think it would be very important to look at.
I think it's becoming increasingly important
in sporadic colon cancer
and one of the important chemopreventive agents for sure.
You know, it would be tough I think in a retrospective way.
A lot of people take multivitamins
and it'd be hard to control for.
And if you go back and do these retrospective studies,
nobody writes down in their notes
whether the person is on Vitamin D or calcium
so I think it would be hard to do.
But I think in a prospective way it would be very important.
The microbiome is fascinating.
I mean, I think that no one's looking at it
yet in this setting
but people are clearly looking at the microbiome
in terms of causing colitis in the first place.
And it might be intriguing
if there is a different progression,
left side versus right side.
Is the ecology, the microflora,
different in the left versus the right?
I think that's a very tantalizing hypothesis
but it needs some data, Dean.
- Does anybody see aberrant crypt foci in IBD?
- The question is, is there aberrant crypt foci in IBD?
I don't think anybody calls them aberrant crypt foci in IBD
but I'm not aware.
Henry, maybe you can answer that.
I don't see that in a colectomy specimen
where you have the whole thing rolled out.
- You don't know it.
(loud laughing)
- Don't ask-- - I've got too many ethics.
- Yeah, I don't think people have really reported that.
Henry, yes, go ahead.
- See, you put down a lot of data about progression
based on a number of different studies
and the studies are probably not comparable
in terms of protocol sampling.
- Absolutely.
- What is the impact of sampling on progression?
- Well, you know, that's why Peter did the modeling study,
is because most of the time
we're taking 20 biopsies or less.
What is interesting is you're absolutely right.
In some of these studies
there might have been 10 biopsies done but it's interesting.
If you think about it,
even though we've been doing a suboptimal number of biopsies
are we causing any harm?
When you think about it,
the dysplasia rates seem to be going down.
I mean, if we were really missing a lot of things
because we weren't taking enough biopsies,
we probably would see it.
We would see more breakthrough cancers.
We would see more breakthrough high-grade dysplasias.
We're not seeing that.
Most centers that I'm aware of are not seeing
these sort of breakthrough cancers.
So even though it's nice to say
you should be doing 30, 40 biopsies,
no one does it and I think frankly
it ain't all that harmful.
And I think Peter's study was important
because it says that the reason
you may not find it with so few biopsies
is because the field effect
may not be as large as we thought.
The field has to be larger,
the dysplasia field in the colon has to be larger
to be able to pick it up with some random biopsies.
- Maybe some of these progression data,
had more biopsies been taken,
may not have been progression
but it would have been incident dysplasia instead.
- Yeah, correct, you're absolutely right
and everybody does things differently
but, I mean, I think this is the failing of...
You know, that's why I put in that Winston Churchill's.
You know, it's not the greatest data
but it's the best that we have, yes.
- Many of these progression studies,
they plot the data based on the kind of diagnosis.
I just wanted to (mumbles) control duration of disease.
Do people look at this in terms of duration of symptoms?
(mumbles)
- Yeah, I think maybe the question you're getting at is
can you start the clock
from the age of onset of colitis, right?
Because if I'm interpreting this right,
you're finding dysplasia at a certain point in time
but how do you know there wasn't dysplasia before that or...
And the age of onset of colitis,
so you have the duration of disease in that sense,
some studies say that younger age
is a higher risk of getting cancer.
The problem with that is the younger you are,
usually the more years of colitis
you've had to get your cancer.
So if you separate out disease duration
from age of onset usually that drops out.
So we don't believe that age of onset
by itself is a risk factor.
It's the duration of colitis,
with all of the failings
of understanding what that really is.
When did colitis begin?
Somebody who has three years of intermittent diarrhea
maybe even with blood but didn't get a colonoscopy,
do you time it from their first colonoscopy
or do you time it from the very first bloody stool?
And studies have done things differently
so we don't really know.
I mean, disease duration is a little bit of a moving target.
Thank you.
(crowd applauds)