
An iPhone App Offers Quick and Inexpensive Melanoma Screening - srikar
http://www.uh.edu/news-events/stories/2014/May/0506ZouridakisDermoScope.php
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rfatnabayeff
The technique is reported to be 85% accurate. That is, there's 15% chance of
false positive. According to wikipedia
([http://en.wikipedia.org/wiki/Melanoma#Epidemiology](http://en.wikipedia.org/wiki/Melanoma#Epidemiology)),
upper bound for melanoma incidence is 20 per 100000 inhabitants. Consider that
100000 people used the technique to screen themselves. There would be 15000 of
them that would got the positive test result and only 20 of them who have
melanoma. Thus, for a person having the positive result the probability that
he indeed has the melanoma is LESS than 0.013%. That is , the probability of
that the technique is reporting B.S. is over 99.8%.

Influenced by recent HN post:
[https://www.sciencenews.org/blog/context/doctors-flunk-
quiz-...](https://www.sciencenews.org/blog/context/doctors-flunk-quiz-
screening-test-math)

~~~
DanBC
There's not enough information to know what "85% accuracy" means. Is that
false positive, or false negatives, or a combination of both, or misreporting?

I agree that presenting risks as percentages instead of real numbers is
misleading.

But they say this device is better than primary care doctors so I'm not sure
what that says about primary care.

Gerd Gigerenzer wrote a book in 2002 about clinicians inability to understand
percentages and screening tests.

[http://www.amazon.co.uk/gp/aw/d/0140297863?pc_redir=13991465...](http://www.amazon.co.uk/gp/aw/d/0140297863?pc_redir=1399146585&robot_redir=1)

[http://plus.maths.org/content/reckoning-
risk](http://plus.maths.org/content/reckoning-risk)

[http://www.amazon.com/gp/aw/d/0140297863?pc_redir=1399339535...](http://www.amazon.com/gp/aw/d/0140297863?pc_redir=1399339535&robot_redir=1)

~~~
lttlrck
"But they say this device is better than primary care doctors so I'm not sure
what that says about primary care."

Only that primary care providers are not specialists.

But your point is important: is using this device as a gateway to
dermatologist referrals a good thing.

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fredley
Single-image analysis is never going to be that accurate unless you've got a
melanoma which already is very advanced. Detecting a changing lesion is a much
more effective way of spotting a potential melanoma, and can catch something
much sooner than these apps, many of which have come before.

Disclosure: I work for Skin Analytics [http://skin-analytics.com](http://skin-
analytics.com)

~~~
MrBuddyCasino
Can you comment on the dermoscope? I'm curious why something like this costs
500$ - it sounds like a plastic lens and some LEDs would fit the job
description.

~~~
fredley
A dermascope uses different wavelengths of light to get a picture of what's
going on slightly below the skin as well as on its surface. This requires
special lenses and lights, which I imagine are not used outside of this
specific case, hence the cost.

~~~
Angostura
I wonder if the iPhone 5s fingerprint scanner could be hacked to produce a
rudimentary system it is meant to to involve 'subdermal scanning' according to
the Apple marketing department.

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nkuttler
Interesting. Somewhat similar to a story that was posted yesterday,
[https://news.ycombinator.com/item?id=7703871](https://news.ycombinator.com/item?id=7703871),
[http://www.npr.org/blogs/health/2014/05/06/309003098/chemist...](http://www.npr.org/blogs/health/2014/05/06/309003098/chemist-
turns-software-developer-after-sons-cancer-diagnosis)

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akie
Not to be snarky, but this is only inexpensive when you already have the $600
phone.

~~~
k-mcgrady
Did you read the article? It also requires a $500 camera attachment device. It
seems to be aimed more at local doctors than regular consumers and has an
accuracy rate higher than the average primary care physician accuracy rate.

