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$5 device tests for breast cancer in under 5 seconds: study

studyfinds.org

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Re: $5 device tests for breast cancer in under 5 seconds: study

#101

Post by wolverine876 »

bookofjoe wrote: post #98
kenjackson wrote: post #78

Earlier quoted context omitted.

And this result probably helps the funding to get more patients. I’ve never worked in clinical trials but it seems like it would be so tiresome.

I ran many clinical trials during my career as an academic neurosurgical anesthesiologist. "... it seems like it would be so tiresome" is accurate; it's also exhausting in terms of the huge amount of time and effort required to get a study approved by the institutional review board; getting informed consent from prospective patients after an exhaustive explanation repeated over and over to each individual; actually d…

So how do you feel about it? :) Seriously, what are you feelings about it after all those experiences?

You forgot the end of the story: After all that, it's done and published, and then a random person with no expertise and who barely read the paper posts on HN: the sample size is too small - as if you were in your first week of statistics 101 - and therefore the whole thing must be invalid! :)

Re: $5 device tests for breast cancer in under 5 seconds: study

#102

Post by lazyasciiart »

jncfhnb wrote: post #85
ethanbond wrote: post #73

Earlier quoted context omitted.

If you're really good at statistics, you can just intuit what seems like a sufficient N. This is actually a powerful statistical method because you can vary your intuition depending on whether you want to believe the study was well-powered or not, enabling you to easily discard Bad Evidence and include Good Evidence. Few understand this.

No, that’s utter nonsense. Statistical power is well defined and the required N to reliably detect an effect is a function of its effect size, which is the thing that wannabe statisticians don’t understand.

> you can vary your intuition depending on whether you want to believe the study

I suspect it is deliberate nonsense.

Re: $5 device tests for breast cancer in under 5 seconds: study

#103

Post by solardev »

lazyasciiart wrote: post #102
jncfhnb wrote: post #85

Earlier quoted context omitted.

No, that’s utter nonsense. Statistical power is well defined and the required N to reliably detect an effect is a function of its effect size, which is the thing that wannabe statisticians don’t understand.

> you can vary your intuition depending on whether you want to believe the study I suspect it is deliberate nonsense.

> I suspect it is deliberate nonsense.

But is that your intuition talking?

Re: $5 device tests for breast cancer in under 5 seconds: study

#105

Post by aeyes »

yakito wrote: post #24

As a reference. Currently an MRI scan can go from $400-$2000 (mostly covered by insurance) https://scan.com/body-parts/breast An MRI machine cost arounds $350.000 on average. https://www.blockimaging.com

MRI is very rarely used for breast cancer screening. Mammography is much cheaper.

Re: $5 device tests for breast cancer in under 5 seconds: study

#106

Post by e63f67dd-065b »

jncfhnb wrote: post #57
e63f67dd-065b wrote: post #12

Press release: https://publishing.aip.org/publications/latest-content/would... Actual publication: https://pubs.aip.org/avs/jvb/article/42/2/023202/3262988/Hig... Experiment size is literally N=21, with 4 healthy participants, 3 in-situ breast cancers, and 14 invasive breast cancers. N=21 might as well be useless in my opinion. You can't draw any meaningful conclusions about statistical power of this test; if your pr…

You can absolutely draw conclusions about the statistical power of the test. That’s what statistics is for. If this sample data is randomly sampled it looks like it will be a fairly high precision test for invasive cancers, with room for false negatives. You would have had to have gotten very unlucky to see such a difference in distributions even on a small sample like this. But sure, let’s get more samples.

It's been a while since I took statistics, but isn't the whole point of testing that it needs to have a high Bayes factor, and to be confident that said Bayes factor is high?

In this case, and my lack of understanding in both bio and stats is showing here, we're trying to develop a test for breast cancer. An ideal test will have high sensitivity and specificity, and a tight confidence interval for both of those numbers. This way we can be confident that a positive/negative test actually moves our priors meaningfully in either direction.

I guess my question/comment is more on the fact that I don't see how any of the results shown actually translate, as the headline suggests, into a cancer test of high power. The priors for any kind of cancer is pretty low from what I can find, so we need high power tests in both the positive and negative direction to meaningfully effect health outcomes. I can't find any CI numbers in the paper, which may just be me not reading it closely enough, but it doesn't help my confidence.

Re: $5 device tests for breast cancer in under 5 seconds: study

#107

Post by dheera »

pvaldes wrote: post #58
dheera wrote: post #52

Earlier quoted context omitted.

No, not at all. Polar opposites. Theranos was actual lies. TFA is just being honest about a low sample size.

If somebody claims: our device "accurately tests", and we discover later that "In fact the tests hadn't been done still" (at a meaningful way), It should be taken as a red flag. Specially when it came in the same package with "to make lots of tests would be really cheap" (but for some reason they didn't tried it). Maybe be a great, honest work, brilliant step?. Yes. But please don't claim that your model is reproduci…

> didn't ever tried seriously to reproduce it first

Maybe they found something worth testing and just need more funding to actually do the tests?

I have no problem with early free speech about "I found something interesting" as long as you're honest about the sample size and don't misrepresent it.

Re: $5 device tests for breast cancer in under 5 seconds: study

#108

Post by renewiltord »

hn_throwaway_99 wrote: post #64
jncfhnb wrote: post #57

Earlier quoted context omitted.

You can absolutely draw conclusions about the statistical power of the test. That’s what statistics is for. If this sample data is randomly sampled it looks like it will be a fairly high precision test for invasive cancers, with room for false negatives. You would have had to have gotten very unlucky to see such a difference in distributions even on a small sample like this. But sure, let’s get more samples.

Thank you for this! I get frustrated with the "N of only 21? Might as well flip a coin!" responses. Like you say, the whole purpose of statistical testing is to give an accurate, numeric value that says how likely the results are due to chance. One thing I'd note, though, is that the paper's title is "High sensitivity saliva-based biosensor in detection of breast cancer biomarkers: HER2 and CA15-3". My understanding…

This is why science has gotten harder these days. When there were only half a billion people, sampling 500 got you 1 in a million coverage. Now there are 8 billion people, so it's worth 16 times less. As more people are made, science will suffer because the percentage is so much less. In fact, this is why I always trust science in small towns more. In Colma, for instance, you sample 500 and you have covered 33% of the people. Sometimes, it's even better to just sample people in one house. 100% coverage.

Re: $5 device tests for breast cancer in under 5 seconds: study

#110

Post by chaxor »

sonicanatidae wrote: post #83
pvaldes wrote: post #37

Earlier quoted context omitted.

> We tried it with 21 people The new Theranos is here again

Not quite. Theranos was stating that they were capable of doing what was impossible prior. The real issue with Theranos was physics. A single drop of blood is simply not a large enough sample for them to do all the testing they claimed. As in, impossible with today's tech and in the near future. These folks are just stating that, "so far, this looks promising". At least, thats my read. YMMV.

It is important to point out that what they claimed to do is not technically impossible actually. They just didn't do it, and lied about it. That was the real problem.

It's very unfortunate, because it is technically possible, just very difficult to achieve, even in academia (so it won't be done first in industry).

This was the absolute worst part of Theranos, is that they deter others from trying to make headway in the space at all.

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