

A Device Could Detect Dozens of Cancers with a Single Blood Test - elleferrer
http://www.wired.com/2014/10/miroculus/?mbid=social_fb

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skue
No, no, no. This is a perfect example of why everyone should be required to
learn statistics.

We don't need a device to do multiple simultaneous screenings. If this were
important, we'd already be doing multiple manual screenings and there would
already be a demand for simplifying it. But there's a very good reason we do
not do mass screening for cancers and other serious diseases with low
incidence, no risk of transmission, and invasive treatment regimens.

Medical tests are not crystal balls. Any test you perform has a risk of false
positives and a risk of false negatives, and even if you have a test with good
_specificity_ and _sensitivity_ , applying any test to any large population
with a low incidence of disease guarantees that most of the positive findings
will be wrong.[1]

Telling hundreds of thousands of healthy people that they have cancer and
sending them through intensive workup and/or treatment when they actually do
not is emotionally and financially harmful to them and the broader community.

This is why we do _not_ do population-wide CT screening for lung cancer, why
we no longer stress that young women without other risk factors have
mammograms (but can choose to if they are risk averse and are okay with
potentially receiving unnecessary treatment), why we are moving away from
aggressive PSA screening, etc.

What's the alternative? Targeted screening. If you reduce the size of people
you screen to those most likely to be affected, then you dramatically improve
your results. So people with symptoms (obviously), people with certain
exposures (asbestos), genetic predispositions to certain types of cancers
(BRCA), etc. In other words, the thing that works best is what we already do.

[1]:
[http://en.wikipedia.org/wiki/Sensitivity_and_specificity#Wor...](http://en.wikipedia.org/wiki/Sensitivity_and_specificity#Worked_example)

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kolev
Very well-said! Finally doctors are realizing that not all prostate cancers
require a "treatment" \- so many men undergo unnecessary surgeries and so many
women followed the advices from celebrities to part with their breasts as a
"preventive" measure instead of, let's say, drink green tea, eat mushrooms
daily, take vitamin D, glucaric acid, and a few other affordable supplements.
I highly recommend the book "The Decision Tree" by Thomas Goetz, who's a
former editor at Wired magazine.

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kolev
Aren't we all having some cancers cells in our blood and lymphatic fluids, and
tissues, but those with a healthy immune response have nothing to worry about?
In most cases, doesn't cancer take years to fully developed helped by
epigenetic factors, but predominantly by the external ones? Won't such device
when massively used for blood testing lead to predominantly false positives,
redundant biopsies, and overtreatment? I think this is a great device with an
enormous potential if used on narrow targets and responsibly, in general. I
just think focus should be on true prevention, i.e. dietary and lifestyle
changes, and not developing a false sense of assurance by living unhealthily
and relying on a test to catch the results of the poor habits, and also rely
on medicine being advanced enough to correct our mistakes. Of course, some
factors are unavoidable today, but we also have a growing arsenal of knowledge
and means to counter many of them.

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trhway
in general your post says that cancer is karma payback, a disease of "dirty
hands". Typical attitude of a "holier than thou" type until your get it
yourself.

> those with a healthy immune response have nothing to worry about?

wrong. Cancer cells are your own cells and in general immune system have no
reason to target them.

~~~
kolev
No, "karma" and "payback" do not belong to my vocabulary. Also, read more -
the immune system is totally capable of attacking some cancer cells [1].
Immunotherapy is what I think will cure cancer paired with better early
detection and prevention with lifestyle and nutrition changes.

[1]
[http://www.cancer.org/treatment/treatmentsandsideeffects/tre...](http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/immunotherapy/immunotherapy-
immune-system)

