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How often do full-body MRIs find cancer?

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Re: How often do full-body MRIs find cancer?

#241

Post by masterlee_fn »

danw1979 wrote: post #227
_alternator_ wrote: post #208

Earlier quoted context omitted.

The major reason not to do this is that you often get worse outcomes for patients. Oncology provides a lot of examples where “more knowledge” does not lead to better outcomes. Routine ovarian cancer screening, prostate screens, childhood neuronlastoma screens, and breast cancer screens all have shown that overuse will identify more cancer, but do not lead to better outcomes like reduced mortality. The reasons are com…

I’m married to someone running various prostate cancer studies in the UK. I hear the arguments against screening a lot and the issue really blew up recently in the news here. The thing is, when researchers talk about “worse outcomes” they’re often comparing survival (or rather lack of) against terrible side-effects. What this fails entirely to capture is that doing something to increase your odds of survival, damn th…

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Re: How often do full-body MRIs find cancer?

#242

Post by masterlee_fn »

gjulianm wrote: post #233
danw1979 wrote: post #227

Earlier quoted context omitted.

I’m married to someone running various prostate cancer studies in the UK. I hear the arguments against screening a lot and the issue really blew up recently in the news here. The thing is, when researchers talk about “worse outcomes” they’re often comparing survival (or rather lack of) against terrible side-effects. What this fails entirely to capture is that doing something to increase your odds of survival, damn th…

> What this fails entirely to capture is that doing something to increase your odds of survival, damn the consequences, is an individual choice. What you're failing to capture is that this is a hard problem because it's both an individual choice and a collective one as well. Those "terrible side effects" might actually end up killing someone. You're choosing between a high-chance lottery on a small population or a lo…

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Re: How often do full-body MRIs find cancer?

#243

Post by masterlee_fn »

_alternator_ wrote: post #217
mvdwoord wrote: post #211

Earlier quoted context omitted.

I appreciate that, but do wonder, if this is an issue with too much data or how we act on that data. In other words, could there be a future where we do have tons more data, but also use the data in such a way to achieve an overall better outcome for patients?

Ultimately its a balancing act between what we can know and what we can do about it. If you can’t treat a cancer (or your treatment is not effective, cf the radical mastectomy) then knowing who has it doesn’t help. As technology progresses and more cancers become readily treatable, it will make more sense to do early screening, and potentially full body MRIs. But right now it is likely to cause a huge waste of time,…

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Re: How often do full-body MRIs find cancer?

#244

Post by [deleted] »

mgraczyk wrote: post #120
vasco wrote: post #118

Earlier quoted context omitted.

You a-priori do not know if you have cancer. The case 1 branches are: Case 1 without cancer: you're a guy that knows more than doctors because you're the "I have 3 scans on hand guy", so as soon as you open the scans and the doctor says there's a mass, you will say 'OK what can we do???' And then you had a worthless biopsy. Case 1 with cancer: you saved the 1 week it would take to schedule the new scan and get result…

That's not how it works. Without the history of scans spaced out in time, they would typically need a biopsy. Multiple scans over time shows change and growth and improves the likelihood of an accurate triage And for the first part that doesn't happen in my scenario before the doctor doesn't look at the scans

[deleted]

Re: How often do full-body MRIs find cancer?

#245

Post by gjulianm »

OneDeuxTriSeiGo wrote: post #184
gjulianm wrote: post #169

Earlier quoted context omitted.

> it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives. Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate. > To use a software anal…

> Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate. This is the main reason. Well technically the opposite of the main reason but more or less it's the same. MRIs are extremely high fidelity nowadays and as a result it's really really hard to read an MRI. Every person i…

> That's actually exactly why it's important to have MRIs more frequently to be able to establish baselines and identify trends as they develop.

How? How do you establish baselines? How do you build a classification of incidental findings? It's very possible that you'll find a lot of types and not a lot of representatives of each type. And then you have to correlate that to actual clinical results, but the population will be so heterogeneous that it'll be really hard to find an actual result.

It's not just "let's throw more data at the problem".

Re: How often do full-body MRIs find cancer?

#246

Post by gjulianm »

buckle8017 wrote: post #205
gjulianm wrote: post #169

Earlier quoted context omitted.

> it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives. Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate. > To use a software anal…

> We already have a lot of MRI data. That's true but not in a useful way for improving MRI screening. What we have is lots of days from people who were sent to get an MRI because they had a complaint. That's a very different group than people doing screening.

And the fact that they have a complaint (or have known risks) makes it easier to classify, compare and understand the data.

Re: How often do full-body MRIs find cancer?

#247

Post by gjulianm »

terminalshort wrote: post #190
gjulianm wrote: post #169

Earlier quoted context omitted.

> it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives. Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate. > To use a software anal…

We do not have a lot of MRI data. The average person probably gets a couple MRIs in their lifetime, and this is biased because we wait until something is clearly wrong to get the MRI. If you want to find an MRI scan of an early stage asymptomatic cancer, the only data on that will be the exceedingly rare case that someone has something else unrelated wrong with them in the same general area and gets an MRI for that,…

> we wait until something is clearly wrong to get the MRI. f you want to find an MRI scan of an early stage asymptomatic cancer, the only data on that will be the exceedingly rare case that someone has something else unrelated wrong

Not always. There are bunch of studies for MRI screening in high-risk populations for specific cancers. There are scoring systems for a lot of them based on imaging features and they do find asymptomatic cancers.

In fact, if you add low-risk populations to the studies used to design imaging scores, you might end up adding more noise and making the study more difficult and the scoring less accurate.

Re: How often do full-body MRIs find cancer?

#248

Post by ErroneousBosh »

codethief wrote: post #178
ErroneousBosh wrote: post #124

Earlier quoted context omitted.

> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed. My mum gets scanned a little more frequently than that, following treatment for an inoperable tumour in her lung around five years ago. During treatment she was getting scanned every three months or so, and it was remarkable watching this t…

> in Scotland where we have (possibly as a result of the weirdly high levels of cancer) Interesting, I had no idea and just looked this up[0]: > Scotland had the highest overall incidence (446 for men and 379 for women per 100 000), and Wales had the second highest rate (450 and 366 per 100 000), compared with 394 and 338 per 100 000 in England and 394 and 345 per 100 000 in Northern Ireland. This would make Scotland…

> PS: Glad to hear your mom is doing well!

Thanks, she had little to no side effects from the experimental immunotherapy drug. She'd said at the outset she didn't want to be a "chemo zombie" having been through all that about 20 years ago (she's had four different cancers throughout my lifetime, treatment getting better every time).

It's fucking expensive, but immunotherapy is really a miracle cancer treatment. We're not quite at "Oh you've just got a wee bit of cancer, we can give you something for that if you see the pharmacist on your way out" but we're not far off.

Re: How often do full-body MRIs find cancer?

#249

Post by ErroneousBosh »

rustyhancock wrote: post #125
ErroneousBosh wrote: post #122

Earlier quoted context omitted.

> The danger of an unnecessary CT/PET is causing cancer You'd have to be massively overexposed to CT or PET scanning to cause cancer, like in the region of spending months being scanned continuously with it at full beam current.

Even if you don't agree with linear no threshold models for cancers induced by radiation (I don't think LNT is accurate). It comes down to the scan and the age. 3 scans for a 1 year old? Strongly associated with cancers later in life. 5 scans of a 50 year old? Less so. The 1 year old has an 80 year run way to develop cancer, along with cells already set in a state of rapid division, and a less developed immune system…

> 3 scans for a 1 year old? Strongly associated with cancers later in life. 5 scans of a 50 year old? Less so.

Someone being born with no legs is strongly associated with them using a wheelchair in later life.

Why are you giving a one-year-old three CT scans? For shits and giggles? Or because you think they might have cancer?

Re: How often do full-body MRIs find cancer?

#250

Post by blueprint »

_alternator_ wrote: post #208
nayroclade wrote: post #129

Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them. Yes, right now MRIs are expensive and false positives are common, but if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives. To use a software analogy…

The major reason not to do this is that you often get worse outcomes for patients. Oncology provides a lot of examples where “more knowledge” does not lead to better outcomes. Routine ovarian cancer screening, prostate screens, childhood neuronlastoma screens, and breast cancer screens all have shown that overuse will identify more cancer, but do not lead to better outcomes like reduced mortality. The reasons are com…

Then they should decide not to treat certain things and have better criteria around that than choosing to bury their heads in the sand and letting people die out of their ignorance.
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