Comment by sungam | Hacker News Reader

Comment by sungam | Hacker News Reader

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Thanks for your comment. The main motivation for me in developing the app was that lots of my patients wanted me to guide them to a resource that can help them improve their ability to recognise skin cancer and, in my view, a good way to learn is to be forced to make a decision an then receive feedback on that decision.

For the patient I think the decision actually is binary - either (i) I contact a doctor about this skin lesion now or (ii) I wait for a bit to see what happens or do nothing. In reality most skin cancers are very obvious even to a non-expert and the reason they are missed are that patients are not checking their skin or have no idea what to look for.

I think you are right about the incidence - would be better to be a more balanced distribution of benign versus malignant, but I don't think it would be good to just show 99% harmless moles and 1% cancers (which is probably the accurate representation of skin lesions in primary care) since it would take too long for patients to learn the appearance of skin cancer.

> most skin cancers are very obvious even to a non-expert and the reason they are missed are that patients are not checking their skin or have no idea what to look for

I am a skin cancer doctor in Queensland and all I do is find and remove skin cancers (find between 10 and 30 every day). In my experience the vast majority of cancers I find are not obvious to other doctors (not even seen by them), let alone obvious to the patient. Most of what I find are BCCs, which are usually very subtle when they are small. Even when I point them out to the patient they still can't see them.

Also, almost all melanomas I find were not noticed by the patient and they're usually a little surprised about the one I point to.

In my experience the only skin cancers routinely noticed by patients are SCCs and Merkel cell carcinomas.

With respect, if "most skin cancers are very obvious even to a non-expert" I suggest the experts are missing them and letting them get larger than necessary.

I realise things will be different in other parts of the world and my location allows a lot more practice than most doctors would get.

Update: I like the quiz. Nice work! In case anyone is wondering, I only got 27/30. Distinguishing between naevus and melanoma without a dermatoscope on it is sometimes impossible. Get your skin checked.

Thanks for your kind words with regards to the app and well done for getting such a high score!. I agree that BCC is often subtle. My practice is also largely focused on skin cancer. I would say that the majority of melanomas (and SCCs) that I diagnose would be obvious to a patient that underwent a short period of focused training and checked their skin regularly. A possible explanation for the difference in our experience is that the incidence of skin cancer (and also atypical but benign moles) a lot higher in Australia than in the UK.

There would be quite the difference in our patient demographics.

I have quite a few patients from the UK who have had several skin cancers. Invariably they went on holidays to Italy or Spain as a child and soaked up the sun.

Keep up the great work.

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