New cancer screening test is accurate enough for rollout.

[Peelee]

https://www.theguardian.com/society/...-be-rolled-out

50% false negative rate, 0.5% false positive rate, across all stages of 50 cancers. This will save millions of lives.

[Rakaydos]

https://www.theguardian.com/society/...-be-rolled-out

50% false negative rate, 0.5% false positive rate, across all stages of 50 cancers. This will save millions of lives.

Standard rare-disease disclaimer, though... 1 in 200 times, you'll be called in for "additional testing", and 1/40,000 times, the second test will also give a false positive... and that's assuming independent random sampling.

If the disease itself is rarer than 1/40,000 patients, false positives are still going to swamp actual positives.

[Peelee]

Standard rare-disease disclaimer, though... 1 in 200 times, you'll be called in for "additional testing", and 1/40,000 times, the second test will also give a false positive... and that's assuming independent random sampling.

If the disease itself is rarer than 1/40,000 patients, false positives are still going to swamp actual positives.

I do not have the numbers on me but I would be surprised of several dozen cancers had less than a .0025% chance of being contracted.

[NichG]

New cancer cases in general seem to be about 4 in 1000 per year. So it'll swamp a one-test protocol, but a two independent test protocol might be ok. I guess the question is how statistically independent are the false positives.

[Rater202]

I read somewhere that at any point in time, 90% of people have some kind of cancer but the body is decently good at isolating and destroying the cells before they spread.

Cancer comes when the malignant cells are particularly virulent, or when something else in the body breaks—apparently, the reason you get sunburns is because some of the cells int he's surface of your skin have become cancerous due to UV exposure and that triggered mass-apoptosis in the affected area. Skin cancer thus comes from this mechanism not working properly.

So, if this is true, and I admit I only saw it in the one place so it might now be, such a much more accurate cancer screening test might be able to find and treat cancers before they even become a problem in some cases.

Better cancer treatments are still needed—we should not be living in a world where someone can decide "you know what, I'm gonna let the cancer run it's course" and have that be a rational decision

But in lieu of better treatments, earlier and more accurate detection is good progress.

[Peelee]

I read somewhere that at any point in time, 90% of people have some kind of cancer but the body is decently good at isolating and destroying the cells before they spread.

Cancer comes when the malignant cells are particularly virulent, or when something else in the body breaks—apparently, the reason you get sunburns is because some of the cells int he's surface of your skin have become cancerous due to UV exposure and that triggered mass-apoptosis in the affected area. Skin cancer thus comes from this mechanism not working properly.

So, if this is true, and I admit I only saw it in the one place so it might now be, such a much more accurate cancer screening test might be able to find and treat cancers before they even become a problem in some cases.

Better cancer treatments are still needed—we should not be living in a world where someone can decide "you know what, I'm gonna let the cancer run it's course" and have that be a rational decision

But in lieu of better treatments, earlier and more accurate detection is good progress.

I'm like 98% sure that's not true; cancer is, at its very basic, uncontrolled cell growth. It's the body's own cells, which means the body is very bad at detecting it as something not desirable, which is the entire reason we have no real natural defenses against cancer to start with.

Further, sunburn is an incredibly accurate name, because it's a radiation burn.

[Rater202]

I'm like 98% sure that's not true; cancer is, at its very basic, uncontrolled cell growth. It's the body's own cells, which means the body is very bad at detecting it as something not desirable, which is the entire reason we have no real natural defenses against cancer to start with.

Further, sunburn is an incredibly accurate name, because it's a radiation burn.

It might be more accurate to say that they're potentially malignant cells that get destroyed before they spread. It's been a while. I'll see if I can find it again.

[Peelee]

It might be more accurate to say that they're potentially malignant cells that get destroyed before they spread. It's been a while. I'll see if I can find it again.

That would be pretty neat. I'm definitely interested in it.

[Yora]

At those chances for false positives and negatives, the method can't really prove cancer.
But given that it can test for 50 different cancers with just one blood sample still makes it seem like a really good way to inform people that they should get a full screening for a specific type of cancer. People wouldn't randomly take 50 cancer tests on a whim, but running a blood sample through this test as part of a regular exam? Sure, why not?

[Rater202]

That would be pretty neat. I'm definitely interested in it.

Well, I can't remember where I read it and it's not in any of the places that I thought to look so just ignore what I said.

At those chances for false positives and negatives, the method can't really prove cancer.
But given that it can test for 50 different cancers with just one blood sample still makes it seem like a really good way to inform people that they should get a full screening for a specific type of cancer. People wouldn't randomly take 50 cancer tests on a whim, but running a blood sample through this test as part of a regular exam? Sure, why not?

Yeah.

Like, I think we all dream of the day when your doctor tells you you have cancer, so you just walk into the local drug store and buy a bottle of Robitussin Cough, Cold, and Cancer and taking that as directed for a week fixes you up, but until that happens every little improvement in finding and treating the disease results in exponential gains when it comes to surviving it.

[Ionathus]

I'm like 98% sure that's not true; cancer is, at its very basic, uncontrolled cell growth. It's the body's own cells, which means the body is very bad at detecting it as something not desirable, which is the entire reason we have no real natural defenses against cancer to start with.

Further, sunburn is an incredibly accurate name, because it's a radiation burn.

As far as I can tell, Rater is closer to the truth here. Sunburn doesn't "burn" you the way touching a hot stove does: it's a bodily reaction to the UV damage in your cells. Skin cells damaged by UV light become a big cancer risk, and as a result your skin cells have a process in place that can trigger them to essentially self-repair, mitigate damage, or self-destruct. Sunburn is the body's reaction to this UV damage, not an actual burn in the traditional sense.

https://www.mdanderson.org/publicati...4Z1591413.html

edit to add:
I always love the chance to share a Kurzgesagt video https://youtu.be/1AElONvi9WQ. Key takeaways:
1. The cells in our body all have kill-switches to make them self-destruct if something goes wrong and they start to grow improperly. That kill switch usually works, but sometimes it doesn't.
2. The immune system kills most of these cancer cells that don't self-destruct...but some can still slip through the cracks. These few surviving cancer cells are the ones that become an actual problem.

[Strigon]

It might be more accurate to say that they're potentially malignant cells that get destroyed before they spread. It's been a while. I'll see if I can find it again.

IIRC, sunburn is essentially just your cells responding to damage to their DNA.
Most DNA damage can be repaired - your cells have a lot of anti-cancer defenses, and most of them work very, very well.

When your skin starts peeling off, that's apoptosis - the cells recognize the DNA is too far gone to reliably be repaired, and they self-destruct.

This is what I've heard. I don't know it's exactly accurate.

[Peelee]

At those chances for false positives and negatives, the method can't really prove cancer.
But given that it can test for 50 different cancers with just one blood sample still makes it seem like a really good way to inform people that they should get a full screening for a specific type of cancer. People wouldn't randomly take 50 cancer tests on a whim, but running a blood sample through this test as part of a regular exam? Sure, why not?

Oh absolutely. Negative is inconclusive, but positive means get more intensive screenings/tests, and if caught in early stage can be lifesaving. This is huge.

[sihnfahl]

we should not be living in a world where someone can decide "you know what, I'm gonna let the cancer run it's course" and have that be a rational decision

But how are we going to get our tales of ordinary people falling to desperation and manufacturing illegal drugs to afford the treatments!?

But in lieu of better treatments, earlier and more accurate detection is good progress.

And in ways that don't have the person go: oh gods, this is a PAIN. (Recent cancer screen for me involved contrast... eeeeek)

[Rakaydos]

But how are we going to get our tales of ordinary people falling to desperation and manufacturing illegal drugs to afford the treatments!?

Dystopian fiction, not dystopian realisim.

[Rater202]

But how are we going to get our tales of ordinary people falling to desperation and manufacturing illegal drugs to afford the treatments!?

Tha'ts a different situation entirely.

Breaking Bad is about a man cooking Meth in order to pay for an untested experimental treatment that might be his only shot at beating an otherwise terminal cancer.

I'm suggesting that we should live in a world where Cancer treatments don't make you feel worse than the cancer does.

Chemo and radiotherapies have some nasty side effects. They'll save your life, but you will feel like **** going through it. For some people, looking at the side effects of the treatments, looking at the odds that the treatment will work, looking at how long it'll take before their cancer becomes symptomatic... Some people choose to just have the cancer. Decide that a longer life isn't worth the side effects of the treatment.

And in some cases, that's a rational decision.

We should not live in a world where choosing not to get your terminal illness treated is sometimes a rational call.

But until we can make treatments that don't make you feel worse than the disease they're curing, catching the cancer earlier and missing less of the cancer means that people won't need as much of the treatment. Three weeks of chemo to make sure after they cut out the itty bitty tumor is a lot more bearable than six months of chemo to try and destroy the malignant cysts all over your abdominal cavity, savvy?

[Ionathus]

Tha'ts a different situation entirely.

Breaking Bad is about a man cooking Meth in order to pay for an untested experimental treatment that might be his only shot at beating an otherwise terminal cancer.

I'm suggesting that we should live in a world where Cancer treatments don't make you feel worse than the cancer does.

Chemo and radiotherapies have some nasty side effects. They'll save your life, but you will feel like **** going through it. For some people, looking at the side effects of the treatments, looking at the odds that the treatment will work, looking at how long it'll take before their cancer becomes symptomatic... Some people choose to just have the cancer. Decide that a longer life isn't worth the side effects of the treatment.

And in some cases, that's a rational decision.

We should not live in a world where choosing not to get your terminal illness treated is sometimes a rational call.

But until we can make treatments that don't make you feel worse than the disease they're curing, catching the cancer earlier and missing less of the cancer means that people won't need as much of the treatment. Three weeks of chemo to make sure after they cut out the itty bitty tumor is a lot more bearable than six months of chemo to try and destroy the malignant cysts all over your abdominal cavity, savvy?

Have you read Atul Gawande's Being Mortal? I think you'd like it.

[MrStabby]

I wonder about some of these false positive and false negative rates - it depends on the exact study methodology.

These are calculated against some baseline. X people with a cancer and Y people without, and how often they get mixed up in the test results... only we don't know how many people in that group it was tested on were actually truely negative - we only know the proportion that tested negative by some other test. Now in some cases that other test we can assume to be reliable - like an autopsy. In other cases we might be comparing one test with another and simply assuming that the other test is reliable. We are not so much measuring accuracy as agreement between tests.

I could see a world where if a test is really good (call it the best test), it can detect signs before any other test. If you then try and validate it by using other tests then some of its true positives will be labled false positives because the less good test didn't pick them up.

In reality I don't think that this is an issue when people live a long life after the test - you get to see the outcome. But with censored data, where say someone gets tested positive then gets hit by a bus and dies... how should you really judge this?


And as always with this type of science - don't forget your Bayes Theorem; if a cancer is sufficiently rare then even a positive result from an accurate test is more likely a false positive than a true one.

[Bohandas]

I read somewhere that at any point in time, 90% of people have some kind of cancer but the body is decently good at isolating and destroying the cells before they spread.

I think you might be confusing "cancer" with "tumors" and/or "genetic damage". IIRC cancer is only when it starts to spread to other parts of the body.

I always love the chance to share a Kurzgesagt video https://youtu.be/1AElONvi9WQ.

Have you ever seen the Sealab episode where Marco becomes obsessed with whale cancer?

[Tyndmyr]

Tha'ts a different situation entirely.

Breaking Bad is about a man cooking Meth in order to pay for an untested experimental treatment that might be his only shot at beating an otherwise terminal cancer.

Only sort of. That's the pitch, kind of, but he very clearly has other options that he's unwilling to take. And he continues long after that's a factor.

It's the inciting incident and a major story point, but the actual cause is far more about pride.

[Kareeah_Indaga]

Dystopian fiction, not dystopian realisim.

Very much this.

I'm suggesting that we should live in a world where Cancer treatments don't make you feel worse than the cancer does.

Chemo and radiotherapies have some nasty side effects. They'll save your life, but you will feel like **** going through it. For some people, looking at the side effects of the treatments, looking at the odds that the treatment will work, looking at how long it'll take before their cancer becomes symptomatic... Some people choose to just have the cancer. Decide that a longer life isn't worth the side effects of the treatment.

And in some cases, that's a rational decision.

We should not live in a world where choosing not to get your terminal illness treated is sometimes a rational call.

But until we can make treatments that don't make you feel worse than the disease they're curing, catching the cancer earlier and missing less of the cancer means that people won't need as much of the treatment. Three weeks of chemo to make sure after they cut out the itty bitty tumor is a lot more bearable than six months of chemo to try and destroy the malignant cysts all over your abdominal cavity, savvy?

+1 all of this. There is a big difference just between three weeks of radiation and six insofar as how horrid you feel, and one of the potential side effects is more cancer. And surgery is isn't exactly pleasant either, nor cheap.

[Peelee]

Only sort of. That's the pitch, kind of, but he very clearly has other options that he's unwilling to take. And he continues long after that's a factor.

It's the inciting incident and a major story point, but the actual cause is far more about pride.

Not even the pitch; all season 1, he was getting the money for his family because he saw his imminent death as a foregone conclusion.

ETA: Which struck me as odd, because in Alabama, public educators get fantastic insurance. It's like one of the biggest reasons to stay teaching, in terms of compensation. But this country is really 50 countries held together by rubber bands so I have no idea what's going on in New Mexico.

[Ionathus]

Not even the pitch; all season 1, he was getting the money for his family because he saw his imminent death as a foregone conclusion.

ETA: Which struck me as odd, because in Alabama, public educators get fantastic insurance. It's like one of the biggest reasons to stay teaching, in terms of compensation. But this country is really 50 countries held together by rubber bands so I have no idea what's going on in New Mexico.

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I mean, the episode Grey Matter is in the first season and it includes Walt getting offered a job (and health insurance) by his old partners. He only turns it down because of his own wounded pride. I wouldn't be surprised if they introduced that plot so early to make it clear that this was never actually about paying for cancer. Doesn't he say in the Pilot "I feel ALIVE" when Jesse asks why he's doing it?

[Tvtyrant]

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I mean, the episode Grey Matter is in the first season and it includes Walt getting offered a job (and health insurance) by his old partners. He only turns it down because of his own wounded pride. I wouldn't be surprised if they introduced that plot so early to make it clear that this was never actually about paying for cancer. Doesn't he say in the Pilot "I feel ALIVE" when Jesse asks why he's doing it?

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One of the overarching motifs of the story is that Walt's ego drives his every move. He hates that he became a public school teacher instead of a millionaire like his friends, that everyone doesn't recognize his greatness. He can't quit once he starts because he is finally getting what he deserves.

[Ionathus]

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One of the overarching motifs of the story is that Walt's ego drives his every move. He hates that he became a public school teacher instead of a millionaire like his friends, that everyone doesn't recognize his greatness. He can't quit once he starts because he is finally getting what he deserves.

I found it! Vince Gilligan literally saying that exact same thing about the episode.