Cancerous Colon Tissue Dr. Andy Connolly of Stanford Medical School shows us what cancerous colon tissue looks like
Cancerous Colon Tissue
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- S: This is Sal again, and this is 4th in a series we're doing here at Stanford Med School w/Dr. Connolly.
- Dr: This is the 4th of the slides, and this would now be the reason why this section of colon was removed.
- This is cancer. So, just to orient. We're going to go to drawing.
- Like you said before, this is the lumen, the inside. Out here is the rest of your belly.
- S: Is there a word for your abdominal [insides]?
- Dr: Peritoneal. So the peritoneal cavity is where all the bowel loops are just moving around.
- What we have here is an important part, this is the muscle that allows peristalsis.
- S: The undulating motion to push stuff.
- Dr: Yes. It will milk it along. So the muscle is all fine there, that's how thick it's supposed to be,
- and it's all fine here...
- S: What scale is this? How thick is that muscle?
- Dr: Our tiny little red blood cells are those tiny dots there, and so we're talking thickness here of
- about a few millimeters.
- S: So that muscle is a few millimeters.
- Dr: Right. So remember that guy was about 6mm? That's about 6mm.
- Dr: That's actually strong, a very strong muscle, you can kinda see it go up here,
- it comes around here, but it looks like it's trouble along this area.
- S: And this stuff was probably once a polyp and it just turned into this massive polyp?
- Dr: Yes. So, we have the normal here, for the lining, this is where it's going dysplastic.
- There's where it's going dysplastic.
- And so now what happens is you got these edges of dysplasia..
- S: When people in the medical field say "plastic," they word means...tissue?
- Dr: Plastic in general, like plastic surgery, or the plastics in material science,
- means moldable. It also means you can grow, you can change shape.
- S: So when you call something plastic, it's moldable tissue?
- Dr: It's the shape changes. So the shape changes were wrong.
- Actually, dysplasia can refer to a cell, tissue, an organ, or an entire limb.
- It just means that it grew wrong, it molded wrong.
- So now, this is where we have the cell dysplasia,
- this is all the bad stuff. It basically started somewhere up there and started invading.
- S: Just one cell up there started dividing uncontrollably.
- Dr: Right. It could have started from one cell being very bad,
- it often starts though from one of these, meaning maybe a cell went bad right around there,
- Now it's really starting to grow.
- S: When you say grow, not the one cell but all of its descendants?
- Dr: Its descendants. Millions and billions are now growing downward to now, in this case,
- grow all the way through. And so you can see the scale is it not only grew a little bit,
- it went right through the muscle.
- S: The body does have some things to fight this off? But it was unsuccessful?
- Dr: Right. There are certain conditions where if you decrease the immune functions
- you'll get cancer. It's still argued if when the immune system decreases you get a virus,
- and a virus causes the cancer, or whether the immune system is [actively watching out for cancer].
- S: The whole notion of viruses is fascinating, because a lot of our ancient DNA is from viruses...
- Dr: Yeah. There are some categories, where viruses can get into your DNA and really mess up your DNA,
- and integrate into it, but viruses can also lead to irritation, with more cell growth and [likelihood
- for DNA copy errors].
- So now we're back where we're looking at the cancer that probably started around here,
- and is growing, including spreading all the normal tissue around it.
- Now we're going to look at the cells.
- First, look at the edges of this. We find normal, though not perfectly normal.
- You can see it's a little bit dividing and a little bit irritated. This is irritated along the edge.
- S: Hyperplasia.
- Dr: Exactly! What we have when we go deeper, this is all coming out, growing in all directions,
- this is where you can see cancer next to the normal.
- We talked before about dysplasia, but this right here is really bad.
- These are the normal ones, they're doing their job. They're making mucin, nuclei at the bottom,
- What is this guy doing? It's just chaos. Before we talked about carcinoma in situ,
- a cancer in a spot--if you saw cells this bad, you'd say, do not let them go far.
- Because they will have a tendency to invade. They're crazy. So this right here is a bunch of the cells,
- this is a bunch of the cells, they're these guys here.
- You can see they're really haphazard in how they're growing,
- they're not doing their job...
- S: If we had a polyp that had this stuff that hadn't crossed that boundary line yet,
- we'd still say, "We got to take this out."
- ...although I guess we already took it out.
- Dr: Cancer of the colon is one of the ones where surgical cures still applies.
- Cut it out, and you are probably in pretty good shape.
- So if it looked like this only at the tip of the polyp, we'd probably got it out,
- But you'd say to yourself, "We better watch this person."
- S: If the whole polyp looked like that, you'd cut out a bigger section?
- Dr: Yes, if it's going down into the neck, or going a little further,
- or if you had cut it across the margin, then watch out.
- But here's the problem: Remember how I said up here it's not a big deal?
- But once you get near the veins and arteries?
- These guys are running amuck, near the veins and arteries,
- S: You can see these cells have split off, and infiltrating...
- Dr: That's one little nest of cells,
- that one is probably a cancer cell just dying to get into that little vein.
- S: So this is metastasis?
- Dr: This is where it would come from. So these guys are the bad actors,
- growing next to these very fragile blood vessels, so that guy is knocking on the door,
- wants to get in here--that's a venule, a little vein, that's the road out.
- S: It looks like a circle here because it's a 2D cross-section of it,
- but you can imagine it popping in and out of our screen.
- Dr: Yes. So this guy might pop in and out of screen, connect to this one...
- S: And it officially metastasized once it's found a beachhead someplace else?
- Dr: Right. It's considered a metastasis if the cell got into the vessel and left the region,
- This is looking like you really are worrying that this could metastasize.
- What's interesting is when you're looking at something like this, there's something called
- pre-cancer grade, and what grade is is what we've been talking about--
- how bad does that look? And so the grade is, "Wow, that looks nasty."
- S: Is nasty a technical term?
- Dr: Actually we use it quite a bit. When we talk about nastiness, it's a lack of behavour,
- if you can get a cell where the nucleus gets that big, or sometimes that big,
- there's chaos. And there's chaos not just in the nuclear size, but how it behaves.
- S: The nuclear size indicates that the cell is devoting cell replication?
- Dr: Yes. But it also means to me--normally things in the cell are very orderly,
- you do not divide your DNA until these things--now it's just left and right.
- This would be a high-grade tumor, and stage is the other main thing.
- Stage means where is it in the body.
- So in this case, if these nasty cells were only at the very top, it would be a lower stage than
- these which have come all the way down here.
- S: In situ carcinoma, what is the stage?
- Dr: Stage 0. It's basically nowhere. If you just begin to crossover, it's stage 1;
- and then there's depth for some stages, and then there's always "did it go to other parts of your body?"
- And that's the very highest stage
- S: And this is true of all cancer--when someone speaks of breast cancer, I've heard of stage 0-4,
- It isn't just the size--if the cancerous tissue is big, but in a safe place, still be stage 1 or 2?
- Dr: It is. The whole world has agreed to the same kind of staging, and that staging is what we're calling TNM.
- T has to do with how big it is, and how much it's crossed any barriers,
- N has to do with if they are in lymph nodes. The lymph nodes are nearby structures where the lymph goes.
- M has to do with metastasis.
- Staging has to do with all three.
- S: Metastases always has to happen through the circulatory system?
- Through the blood vessels, or does it also happen through the lymph network?
- Dr: It's something where going through the lymph nodes is one of the first steps for something like this,
- but getting to the liver or the lung, it's got to get into the blood vessels.
- The lymphatic in your colon connects to a local lymph node,
- but does not connect through lymph only to the (...? be quieter, Sal!)
- So it must have gone through the blood somewhere.
- So that's the way it looks here. And the final thing when looking at this cancer is
- if we go over here, this is the greatest depth of invasion.
- You had asked me about the body's immune function.
- Well, if you look here, you see how it's kind of loose?
- There is all these little immune cells?
- S: What's the immune cells?
- Dr: These guys here. These little round guys? These are lymphocytes.
- S: How can you tell the difference between the lymphocytes and the cancer cells?
- Dr: Because I'm a pathologist...
- They're these little round ones. Right here is a classic cell, which is called a plasma cell
- in which there is a nucleus here, and all the rest is making antibodies
- S: You're not circling that area are you?
- Dr: No, I'm just drawing. So this guy is this one. So I'm zooming in on him.
- Dr: That's a plasma cell, that's making antibodies probably against the tumor.
- That's the immune response in that spot.
- S: How do you know...that looks very similar to the cancer cells?
- Dr: This one is a little hard to tell. If you had a real microscope, you'd turn up the light,
- this would have a very specific look to the nucleus,
- and these guys over here have little pink granules in them,
- which is a type of immune cell.
- S: Which ones are cancerous here?
- Dr: These are all inflammation. The nearest cancer cells are these guys up here.
- S: On this view it becomes obvious, they look different.
- Dr: When you come out here, there's the cancer,
- there's the body's reaction to the cancer.
- There are therapies based on trying to get more of this immune response.
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