Systemic thinking about cancer | Miscellaneous | Heatlh & Medicine | Khan Academy


SALMAN KHAN: This is Sal here. And I have Dr. David
Agus visiting the office. And I want you to
introduce yourself because you have kind
of an interesting life. DAVID AGUS: Interesting
life is scary. But I’m a professor of
medicine and engineering at the University of
Southern California. I treat cancer patients. And I have a lab that looks
at new ways and technologies to understand and treat cancer. SALMAN KHAN: And that’s what’s
really interesting, the fact that you’re a professor of
both medicine and engineering. And I guess that’s
kind of what we’re going to touch on
a little bit here. DAVID AGUS: Yeah. SALMAN KHAN: And so this is
clearly a picture of eggs. Why are we looking at eggs? DAVID AGUS: Well, if
I gave you those eggs, and I put them in your
office, and I say come back in three weeks,
what would you have? SALMAN KHAN: They would go bad. I’m not putting them in
a fridge, I’m assuming. I’m just– DAVID AGUS: You’d
have a rotten egg. Exactly. But if I was clever and
I changed the temperature in your office to 99.5%
degrees Fahrenheit and I rotated those
eggs three times, it has to be an odd number,
then at the end of three weeks, I’d have a chicken. SALMAN KHAN: So that’s
what this other picture is. You’d have this. So you could either
have a rotten egg, so this kind of crazy
mess, smelly thing, or you have this cute,
adorable chicken. DAVID AGUS: Although
they call babies, chicks. SALMAN KHAN: Chicks, or chick. Yes. DAVID AGUS: Yes. So a small change in
temperature and gravity goes from chaos to order. SALMAN KHAN: Right. Right. DAVID AGUS: And so
we’re going to talk in a minute about cancer
and all the chaos that’s involved with it. But realize that
that egg, I changed the temperature and the gravity
and I went from chaos to order. So while will it seem
incomprehensible and unable to model cancer,
you’re going to start to see little changes
can have a major effects. SALMAN KHAN: I see. And this is what’s a
little bit unintuitive. So when think about
things like cancer, I mean cancer is
not the only one, we imagine that we just have
to kind of– we have to kill it or we just have to kind
of have to take it out. But what are saying
is, hey, maybe there’s these subtle things, analogous
to rotating an egg three times and getting the
temperature just right, that can make it automatically
do different things. DAVID AGUS: Exactly. To me, cancer is a
verb, not a noun. So you’re “cancering”– SALMAN KHAN: Cancering. DAVID AGUS: –when
you have cancer. It’s not that you have
cancer, you’re cancering. And so my goal is to change
your state of your body from a cancering to a healthing. And so the first question is
how do you quantity the state? How do we say who
and what you are? And so technology is
giving us the opportunity to do that as we go forward. SALMAN KHAN: Right. I just want to get my head
around that because you never hear that word “cancering.” I think you probably invented
that word, [INAUDIBLE], or healthing. Once again, when
I imagine cancer, I think this is the way
most researchers think about cancers, is
the set of cells that have just gone berserk. And you have to remove them or
kill them somehow or stop them from spreading. And what you’re
saying is, no, there’s something going on systemically
in your body that is cancering. It’s allowing the
cancer to thrive. DAVID AGUS: That’s it. So your first
definition of something you have to cut out, a different
organism, that’s bacteria. SALMAN KHAN: Right. DAVID AGUS: That’s an infection. So if something from the
outside comes inside of you, I give you the
right antibiotic, it doesn’t care if you’re a man
or a woman, you’re six feet or you’re three feet,
if that antibiotic targets the bacteria,
it goes away. The difference in cancer,
it’s your own cells that have gone a
little bit crazy. And so we have to
change the interaction of the body and
the cells in order to make that patient better. Very different than something
without, this is within. SALMAN KHAN: I see. In other words, I’m
just– it’s fascinating because there’s all sorts
of parallels in, I guess, everyday life, depending
on what you believe. But some people, if
there’s crime in an area, there’s one point of view
that you need to police it. You have to arrest
all the criminals. But then, hey,
maybe the criminals keep coming because there’s
certain environmental factors. Maybe there’s just
a lot of poverty and there’s lack of education. And so you’re saying, hey,
let’s look at the things systemically, as
opposed to just– DAVID AGUS: Hunting. Put some lights in the area,
put some police driving by. But all of a sudden, the
crime level goes down. SALMAN KHAN: Right. Right. It’s not just about
arresting the criminals. DAVID AGUS: Exactly. SALMAN KHAN: It’s about
preventing the crime. DAVID AGUS: Let me tell you
about a clinical trial that was done a couple years. It’s the coolest clinical trial. And they took women
after optimal therapy for breast cancer,
these they were women who were
premenopausal, so really aggressive breast cancer. Half of them, after
treatment, got placebo. And half of them got a
drug that builds bone. SALMAN KHAN:
Interesting [INAUDIBLE]. Let me write this down. So this is breast cancer. So these are people– DAVID AGUS: These are young
women with breast cancer. SALMAN KHAN: Right. Right. And half got a placebo, which
means just like a sugar pill. DAVID AGUS: Sugar pill. SALMAN KHAN: And then
you give that to patients just to make them think that
they might– because sometimes the psychological
impact [INAUDIBLE]. DAVID AGUS: And
this was ethical. And it’s very important to talk
about whether it was ethical or not. It was ethical
because they already got their treatment
for breast cancer. And normally in those
women, we just wait. And hopefully, they’re cured. And we see if it may recur. SALMAN KHAN: Right. DAVID AGUS: So in those women,
we divided them into half. And we gave this pill. It was a placebo. And half, we give a drug for
osteoporosis that builds bone. SALMAN KHAN:
Osteoporosis, osteo– DAVID AGUS: You say, why
are you wasting someone with breast cancer’s
time by giving them a drug that targets bone. SALMAN KHAN: Right. Right. Right. DAVID AGUS: The reason is breast
cancer metastasizes to bone. SALMAN KHAN: And
it metastasizes, it spreads to bone. DAVID AGUS: It spreads to bone. SALMAN KHAN: And that’s when
cancer just goes, [INAUDIBLE]. DAVID AGUS: Right. It goes to the bone. It likes the bone. So the argument, if I change
the soil, the seed won’t grow. Because remember, when
you have a garden, you can give your
fertilizer or make that soil so those tomato plants love it. SALMAN KHAN: Right,
right, right. DAVID AGUS: And so that’s
what we’re doing here. We’re making the bone different. SALMAN KHAN: Right. And so once again,
the system thinking is that before, if you have
these breast cancer cells that are just growing, the view
is, hey, let’s irradiate them. Let’s slice them out. Let’s get chemicals that
will be toxic to these cells and kill them. What you’re saying is
cancer really starts to become a real
negative once it spreads. And what you’re saying
is let’s keep it from spreading maybe where
it’s the most common to spread, which is in the bone. So before the bone
drug, the cancer spread. The cancer could kind
of take root in the bone and then start spreading
and metastasizing. This is what metastasis is. DAVID AGUS: Um-huh. SALMAN KHAN: And instead,
you’re saying maybe if you have this special
drugs, this osteoporosis drug, it makes the bone that
much stronger and less susceptible to
this type of thing. And then that won’t
be able to happen. DAVID AGUS: Exactly. SALMAN KHAN: Right. Right. Fascinating. DAVID AGUS: So at the
end of that trial, the cancer recurrence
was reduced by 40%. SALMAN KHAN: Wow. DAVID AGUS: At the end of that
trial, new breast cancer, so a separate breast
cancer– because once you have one breast cancer,
you can get another breast cancer– that was down by 35%, SALMAN KHAN: Wow. DAVID AGUS: So this notion
of changing the system– because remember, this is
a drug that didn’t even touch the breast cancer–
had a dramatic effect in the survival of
these young women. SALMAN KHAN: Right. Right. DAVID AGUS: So
again, it just makes this a whole new way of
thinking about disease. SALMAN KHAN: Right. Right. So if we were putting
words on things, the way that most people think
about disease right now, you call it kind of a
reductionist, where they’re just going to focus on
one narrow part of it. They’re trying to focus on
this thing right over here. And you’re advocating for
kind of a more systemic way of thinking about
it, where you think about everything that
this might involve or that might affect it. DAVID AGUS: It’s so wild is that
for the last several decades, we’re trying to focus on the
individual cell, and then the individual gene, and
then the piece of the gene. And we forgot to
take that step back and look at the whole system. And so remember, the
cancer is your normal cell that’s gone a little bit crazy. So we have to model
that whole system and figure out a way to control
it so the cancer won’t like it. SALMAN KHAN: Wow. Fascinating. Fascinating. And then we have pictures
of what some of these things look like. So what is this right over here? DAVID AGUS: So this is a liver
that’s taken out of a patient. And the white spots
there are colon cancer that’s metathesizes,
again spread to the liver. SALMAN KHAN: Right. So it’s a cancer that
grew up in the colon. And at some point, it was able
to spread and kind of liberate itself and then attach
on to the liver. And it’s metastasized
to the liver. And now, it’s kind of growing
in this– it looks, at least from this picture, kind of
a cauliflower-like shape. DAVID AGUS: Exactly. Exactly. And then if I showed this
to a surgeon, or someone who normally operates
on livers, they would know right away, hey, that
looks like colon cancer gone to liver. SALMAN KHAN: Right. Right. SALMAN KHAN: And if you look at
the next picture on the right, that’s colon cancer inside of a
lymph node under a microscope. SALMAN KHAN: And
these are the lymph? DAVID AGUS: Those are
the normal lymphs. SALMAN KHAN: Lymphs. And this right here
is the colon cancer? DAVID AGUS: Exactly. SALMAN KHAN: OK. DAVID AGUS: And so
any pathologist would look under a microscope and they
would make a diagnosis and say, hey, this looks like colon
cancer gone to the lymph. And in the bottom
is a different way of looking at cancer,
which is a CAT scan. So this is basically a
three-dimensional X-ray. I took a slice
right in the middle that person’s body and those
translucent areas in the middle there are colon
cancer metastasis. SALMAN KHAN: This? DAVID AGUS: Those
darker areas, yes. SALMAN KHAN: OK. DAVID AGUS: And so
what’s amazing is– SALMAN KHAN: That’s
in their liver. DAVID AGUS: Colon cancer looks
a certain way, in a lymph node, in the liver, on a CAT scan. And it always looks that way. The body doesn’t care what
the underlying genetics are because the genetics are
dramatically different patient, to patient, to patient. But it always looks the same. SALMAN KHAN: I see. DAVID AGUS: So
somehow, evolution is selecting out for phenotype,
which is what things look like, not necessarily for genotype. SALMAN KHAN: Which
is their actual– the DNA that makes
up what they are. DAVID AGUS: Exactly. And so we’re
focusing on genotype. And genotype is very
important and it’s going to give us some
understanding over time. But we have to also
take that step back and look at the phenotype, and
look at what it looks like, and try to change
those interactions. Remember, if a patient
has early cancer, we’ve learned a lot
in the last 10 years. So if you have early
cancer, and I cure you with surgery, the day
before surgery I can always find cancer cells
in the blood,– SALMAN KHAN: Wow. DAVID AGUS: –even
though you were cured. So the old days,
we thought, well, you have to wait till it goes
out through our bloodstream and gets out there. That’s wrong. It’s can it live outside
that original organ? SALMAN KHAN: I see. So there’s someone who’s
cured or they’re not cancering right now. And there is actually
cancer in their blood. But because they’re
healthy now, or healthier, or they’re healhing, or I guess
however you want to call it, that cancer isn’t
able to take hold. DAVID AGUS: And
those cells, they can’t live anywhere
but the colon. SALMAN KHAN: Fascinating. DAVID AGUS: So listen
to this experiment. This is the wildest experiment. They took a mouse. And they took breast
cancer and they put it in the left breast
and the right breast. And they colored them
red and green, the cells. They waited a day,
they went back, and the cells were half
red, half green; half red, half green. Because we always
thought if cancer is something in one
local spot, it really is a disease that keep going
through the bloodstream. And it likes those breasts. That’s why it keeps
going back there. SALMAN KHAN: So interesting. And when I always
think of metastases, and I can never say
is the word, I always imagine it, OK, that’s
the cancer that’s finally gotten to
the lymph network. It’s finally gotten to the blood
vessels and now it’s spreading But you’re saying that
there’s actually often cancer that has gotten
to the transportation networks of the body. But it has still
not metastasized because it’s not able
to take hold yet. DAVID AGUS: Exactly. SALMAN KHAN: That’s fascinating. DAVID AGUS: Exactly. And over time, we’re going
to get the technology to interrogate those cells
to say, hey, this one can take hold here. Therefore, I have to change
where it would take hold. We’re just at the beginning
of that technology that’s going to change everything. SALMAN KHAN: And
the reason why we’re looking at these, the
fact that colon cancer starts in the colon and this
is how it looks when it spreads to different parts of the
body, what you’re saying is that we shouldn’t maybe
be so fixated on just the DNA of colon
cancer because it can be very different from
one patient to the next. But maybe on kind of
its macrobehavior, it’s phenotype, how it
looks, and how behaves. And that way,
it’ll give us clues maybe on how we can change it. DAVID AGUS: Exactly. SALMAN KHAN: Fascinating. Thanks a bunch. This is very interesting. DAVID AGUS: It’s great.

47 thoughts on “Systemic thinking about cancer | Miscellaneous | Heatlh & Medicine | Khan Academy

  1. Shouldn't we first find out why these cells are turning into cancer? Drugs, pollution in your water and air you breath. GMO food, pesticides etc. It seems that nobody wants to start with these areas first. Why? Healthcare is a business. Cancer in a business. Cure it and many people are out of a drug.

  2. if sal hadn't grasped what the prof was saying and put it into his own, clearer, words, i wouldn't have understood a thing

  3. very interesting indeed,but how do we know that changing the "soil',in this case 'strengthening' an organ,will not make it more susceptible for cancering?

  4. @f0revern0ty0urs2 because the doctor said he tried this idea on breast cancer patient and it works; he reduced the chance of recurrence.

  5. Man, I loved Dr David Agus, and his explanation, really amazing! I expect that he comes back for another video.

  6. @oozhaboo I have heard about the bodies PH level plays a role in sickness, but I have not read any of the book. Thanks, I will check it out! πŸ™‚ You are what you eat!

  7. 9:05 "Somehow evolution is selecting out for phenotype…." So, what does Ager mean here? Why does he suspect that cancer's looking similar on the surface to an outside observer with a microscope or a CAT scanner would be in evolutionary favor?

  8. @idster7 sorry, Agus*. 9:05 Why does Agus suspect that cancer's looking similar on the surface to an outside observer with a microscope or a CAT scanner would be in evolutionary favor?

  9. That feeling when you click on a video because the thumbnail is a young, good looking chick and you just see a pair of balls when you open it.
    DAMN YOU!

  10. @coburleson This guy says that these cancers only survive under certain conditions. To my understanding, he means if you're liver is in an unhealthy condition, the cancer can take hold. If your liver is healthy, a cancerous cell may occur but would be unable to take hold. Maybe he means some mutagens and/or carcinogens merely encourage cancerous cells to grow, not actually create them?

  11. @coburleson By suggesting people start looking more at the phenotype than the genotype, I think he's pointing out that although genotypes can vary a lot, the phenotype doesn't vary much. Maybe he's suggesting that this phenotype could be a kind of visual indicator as to what is causing the cancer to spread, Maybe a change in the environment has given this cell a huge advantage over normal cells (an advantage it wouldn't find elsewhere in the body). Just maybes and my interpretations πŸ™‚

  12. Very fascinating video giving a unique view on how cancer works. The case study of the mouse showing how the cancerous cells had spread quickly without actually causing a cancer was an eye opener.

  13. @coburleson You and the video creator are clearly talking about different approaches to preventing cancer. You talk about preventing cells from becoming 'potentially' cancerous in the first place, he talks about preventing 'potentially' cancerous cells from becoming actively cancerous. I quote potentially because, until this video, I thought a cell was either cancerous or it wasn't. I didn't know it could be dormant until the right conditions in the body occur. Both angles merit discovery.

  14. @coburleson Nah, I won't! Jumped the gun a little here and went with the basic 'causes cancer' definition. Fail. However, from what he's saying, his approach to preventing cancer would be to prevent cancerous cells (already mutated / damaged) from becoming active. He believes controlling the environment of the cells is the key to this. If he's right, this kind of research could at least slow down cancer whilst it is treated.

  15. Pretty much EVERYTHING in this world is trying to cause cancer in your body, especially the SUN (uv radiation). The risk of cancer developing is greatest when your cells divide, there in lies a chance for error and mutation, thus why your far more likely to get cancer in your colon versus your heart (turnover of cells). Programmed within these cells are specific checks and balances, the most important of which are Tumor Suppressor/Oncogenes which recognizes that these cells are "mutated" and signal for apoptosis. How you lose those gatekeepers is varied from genetics too carcinogens too free radical species and so on. AWESOME video though, a fresh look at an old view is always welcome!

  16. Those changes did not cause a change from chaos to order. Rather, the egg is initially in an ordered state, which follows through into a more complex ordered state by following the specific instructions embedded in DNA. When the conditions are not good, it moves from an ordered state (the egg with the potential to grow) into chaos (the egg which has died and begun to rot).Β 

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