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Deep learning outperformed dermatologists in melanoma image classification task

ejcancer.com

11–20 of 94 posts

Re: Deep learning outperformed dermatologists in melanoma image classification task

#11

This is a great example of where we need to get humans out of the equation when (if) a machine is conclusively proven to perform consistently better. It was justified (cost wise) to replace many human labourers on auto assembly since machines don't get tired, need breaks, have off days. It could certainly be argued it is even more important in the field of health care (reduce costs and improve outcomes) for all forms…

> This is a great example of where we need to get humans out of the equation now that a machine performs consistently better.

No, it's not.

The system is an image classifier with a HUGE false positive rate (and false negative rate). When false positive rates exceed actual incident rates in the population (or far exceed by orders of magnitude, in this case), then it's practically worthless. This is something that the medical community just does not get about statistics (edit: I'm not making a wild generalization here, there are articles out there about this issue).

What this study actually shows is that an image-only diagnosis of melanoma sucks and should never be used. It doesn't matter if it out-performs doctors, because in either case the diagnosis is garbage.

Re: Deep learning outperformed dermatologists in melanoma image classification task

#12
Every doctor tends to have a very static sensitivity-specificity preferences (true positive rate aka recall and true negative rate, respectively). One of the interesting consequences of using an automated diagnostic tool (already mentioned in Esteva et al 2017's Nature article) is that the sensitivity level can be chosen dynamically, depending on additional risk factors.

Re: Deep learning outperformed dermatologists in melanoma image classification task

#13

This is a great example of where we need to get humans out of the equation when (if) a machine is conclusively proven to perform consistently better. It was justified (cost wise) to replace many human labourers on auto assembly since machines don't get tired, need breaks, have off days. It could certainly be argued it is even more important in the field of health care (reduce costs and improve outcomes) for all forms…

Machines will never replace dermatologists, machines will only make them more efficient.

Well... Never say never. If you said machines would not replace dermatologists in the next 1 or 2 decades, I would agree with you. After that, all bets are off.

Re: Deep learning outperformed dermatologists in melanoma image classification task

#14
post #3

I wonder if the results would be similar were the dermatologists to see the actual patient, in person, and then diagnose. And, then a photo was taken to be diagnosed by the CNN. In other words, while dermatologists may have been outperformed by deep learning in image classification, it is not evident if deep learning could do the same against dermatologist diagnosing in person. Also, not clear what the overall ratio…

This is extremely relevant. Factors like whether the patient has freckles or red hair often drive doctors to resect anything out of an abundance of caution. It doesn't look like these additional demographic factors were made available to clinicians.

That said, the results here are still impressive.

Source: I worked in clinical melanoma research for 2 years.

Re: Deep learning outperformed dermatologists in melanoma image classification task

#15

This is a great example of where we need to get humans out of the equation when (if) a machine is conclusively proven to perform consistently better. It was justified (cost wise) to replace many human labourers on auto assembly since machines don't get tired, need breaks, have off days. It could certainly be argued it is even more important in the field of health care (reduce costs and improve outcomes) for all forms…

Machines will never replace dermatologists, machines will only make them more efficient.

Interesting point.

The authors also seem to note this in their conclusion: “Our findings suggest that artificial intelligence algorithms may successfully assist dermatologists with melanoma detection in clinical practice which needs to be carefully evaluated in prospective trials.”

They use the verb assist. I think this will be the case, tools like this will be made available to board certified dermatologists to enhance their work. It won’t replace them anytime soon.

This field continues to be among the most competitive for physicians in the US. The barriers to entry are not only high, the number of residency spots get smaller each year when compared to total applicants. If interested, here’s some stats on med school rankings and derm match results: https://escholarship.org/uc/item/59p3z80r.

But over many years I wonder what will happen. Will there be paradigm shifts that make us rethink about all these specialities and subspecialties? Should we combine them or do something else?

Re: Deep learning outperformed dermatologists in melanoma image classification task

#16
post #5

It's hard to imagine an narrow image classification task that humans will be able to beat NNs.

It's not clear that melanoma diagnosis is fairly described as a static image classification task.

Certainly it's a component, but (for example) patient history is, too.

Re: Deep learning outperformed dermatologists in melanoma image classification task

#17
Maybe a dumb question from a non-medical guy: are medical images considered "stationary" from a stats viewpoint?

That is, will medical images of diseases we diagnose in the next 20 years look a lot like the ones from the past 20 years, or is there a danger of over-fitting on an evolving data set? Could either the technology or the biology of the disease evolve?

In a prior life I was a quant trader, and financial market data is notorious for having the non-stationary problem. On top of market rules and structures changing all the time, once someone discovers a profitable trading idea, their own actions change what the data looks like for everyone else from that point forward.

Re: Deep learning outperformed dermatologists in melanoma image classification task

#18
post #3

I wonder if the results would be similar were the dermatologists to see the actual patient, in person, and then diagnose. And, then a photo was taken to be diagnosed by the CNN. In other words, while dermatologists may have been outperformed by deep learning in image classification, it is not evident if deep learning could do the same against dermatologist diagnosing in person. Also, not clear what the overall ratio…

Maybe? It's hard to say. I had a question about a mole once and what they did was take a photo of it with a special camera apparatus and they sent the image off to be diagnosed while I waited around. The doctor looked at it personally but it seems like the actual diagnosis was made by someone who never even saw me.

Re: Deep learning outperformed dermatologists in melanoma image classification task

#19
well the answer is a bit more complicated than just replacing dermatologists with a CNN. I am pretty convinced the better approach is something like the approach in this paper-use the CNN on easy cases-have the CNN tell a human which instances are hard to classify. Many images are easy to classify-but some are hard [even for the cnn] and humans should give those images more study.

https://arxiv.org/abs/1903.12220

Re: Deep learning outperformed dermatologists in melanoma image classification task

#20
Reporting only sensitivity/specificity/ROC metrics and not reporting precision/positive predictive value is a bad sign. Especially since the latter is what health systems will want to look at before deciding on implementation.

The fact that they fiddled with the balance of classes in the test set makes the above even worse.

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