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Comment by meindnoch | Hacker News Reader

Is this really "invasive melanoma"? https://drmagnuslynch.s3.eu-west-2.amazonaws.com/isic-images...

According to the metadata supplied with the dataset yes

Could definitely be a misclassification, however a small proportion of moles that look entirely harmless to the naked eye and under the dermatoscope (skin microscope) can be cancerous.

For example, have a look at these images of naevoid melanoma: https://www.google.com/search?tbm=isch&q=naevoid+melanoma

This is why dermatology can be challenging and why AI-based image classification is difficult from a liability/risk perspective

I was previously clinical lead for a melanoma multidisciplinary meeting and 1-2 times per year I would see a patient with a melanoma that presented like this and looking back at previous photos there was no features that would have worried me.

The key thing that I emphasise to patients is that even if a mole looks harmless it is important to monitor for any signs of change since a skin cancer will almost always change in appearance over a period of several months

> however a small proportion of moles that look entirely harmless to the naked eye and under the dermatoscope (skin microscope) can be cancerous.

That is very scary.

So the only way to be sure is to have everything sent to the lab. But I'm guessing cost/benefit of that from a risk perspective make it prohibitive? So if you're an unlucky person with a completely benign-presenting melanoma, you're just shit out of luck? Or will the appearance change before it spreads internally?

This is why dermatology involves risk management not just image interpretation. Yes the lesion will likely change with time. Realistically yes, if you have a melanoma that looks like a harmless mole then the diagnosis is likely to be delayed. But remember that these are a tiny proportion of all skin cancers and you are much more likely to get some other form of cancer - most of which occur internally and cannot be seen at all.

This is a good example of what I find frustrating as a patient. Sure, cancers like that may be a tiny proportion of all skin cancers, but if I have it then it's 100% of my skin cancers. And given how serious skin cancer can be, I'd at least want my doctor to let me know how I could get this lesion tested, even if it's out of my own pocket.

The risk of misdiagnosis and thus unnecessary treatment, can mean that such testing can increase your actual chance of dying or decrease your life expectancy. It depends on the case but its why we don't test generically for cancers unless someone is high risk (such as being old)

I agree with you - if a patient is concerned by a specific skin lesion and requests removal then I will support this even it appears harmless particularly if it is new or changing

> According to the metadata supplied with the dataset yes

"idk but that's what it says" somehow this does not inspire confidence in the skin cancer learning app.

Yeah that seems likely to be a misclassification...

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