
Cancer Is More Bad Luck Than Bad Behavior, Study Says - svtrent
http://www.bloomberg.com/news/2015-01-02/cancer-largely-due-to-biological-bad-luck-rather-than-behavior.html
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auton1
This article misstates the finding of the research, as does much of the other
coverage. A good explanation can be found here:
[http://www.theguardian.com/science/grrlscientist/2015/jan/02...](http://www.theguardian.com/science/grrlscientist/2015/jan/02/bad-
luck-bad-journalism-and-cancer-rates)

~~~
tokenadult
Thank you very much for that helpful link. If you submit it as a new
submission to Hacker News, I'm sure I will not be alone in being glad to
upvote it to main page visibility.

~~~
auton1
Thank you. Submitted.

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murbard2
Here's a curve that represents the rate of cancer diagnosis by age in the UK.
[http://www.cancerresearchuk.org/cancer-
info/cancerstats/inci...](http://www.cancerresearchuk.org/cancer-
info/cancerstats/incidence/age/#Cancer)

If cancer were only about a mutation happening randomly, you'd expect the
curve to actually slope downwards, like an exponential distribution.

But maybe cancer requires several mutations to happen in a row, which would
suggest an Erlang distribution of which we only see the beginning of the hump.
20 mutations give a very good curve fit (1).

An alternative hypothesis is senescence. Maybe the mutation rate itself
increases with age, or maybe the immune system isn't as able to nip cancerous
growths in the bud.

This is important! Whenever the impact of a disease doesn't follow a chi
squared or exponential distribution, it suggests two ways to fight the
disease. Directly target the disease itself, or target the process which over
time makes us more susceptible to it.

(1) warning, back of the envelope, there are plenty of other effects to
account

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revelation
That looks like a perfectly fine exponential distribution.

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murbard2
No it doesn't. The exponential distribution p.d.f. is decreasing.
[http://en.wikipedia.org/wiki/Exponential_distribution#mediav...](http://en.wikipedia.org/wiki/Exponential_distribution#mediaviewer/File:Exponential_pdf.svg)

~~~
revelation
But that's not what we are interested in, no? Nobody asks "whats the
probability that you'll get cancer at precisely age x", they ask "what's the
probabiblity that you'll have cancer _by_ age x". I mean, we often can't even
determine at what precise age the cancer developed. That's a problem for the
PDF, not so much the CDF.

~~~
murbard2
The graph I linked to plots the PDF. It's not exponential. It indicates
something is getting worse over time.

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tokenadult
I see the sole previous top-level comment here [edit: which has now been
deleted] started out with a misstatement of fact. In fact, age-adjusted cancer
death rates have been steadily dropping in the United States[1] and in general
death rates from cancer and from other major causes of death have been
decreasing throughout the developed world throughout my lifetime.[2] What that
means in practical terms is that life expectancy at age 40, at age 60, and at
even higher ages is still rising throughout the developed countries of the
world, so if you have reached the age of 50, you can be ever more confident of
reaching the age of 65, and if you reach the age of 65, you can be ever more
confident of reaching the age of 80, and so on.

It is possible for expanded cancer screening programs to produce the illusion
that rates of age-adjusted cancer diagnosis have increased because of a real
increase in cases of cancer,[3] but what is really going on with increased
screening is increased detection of early cases of cancerous growths that
eventually die off and never cause clinical disease. The human body has some
defenses against cancer, and many cancers reach a growth dead-end not long
after starting. Screening programs sometimes detect harmless cancers that
don't need any treatment except watchful waiting.

[1] [http://www.reuters.com/article/2014/12/31/us-cancer-
casualti...](http://www.reuters.com/article/2014/12/31/us-cancer-casualties-
idUSKBN0K918220141231)

[http://www.bloomberg.com/dataview/2014-04-17/how-
americans-d...](http://www.bloomberg.com/dataview/2014-04-17/how-americans-
die.html)

[http://www.slate.com/articles/health_and_science/science_of_...](http://www.slate.com/articles/health_and_science/science_of_longevity/2013/09/life_expectancy_history_public_health_and_medical_advances_that_lead_to.html)

[2]
[http://www.nature.com/scientificamerican/journal/v307/n3/box...](http://www.nature.com/scientificamerican/journal/v307/n3/box/scientificamerican0912-54_BX1.html)

[3] [http://www.sciencebasedmedicine.org/recent-developments-
and-...](http://www.sciencebasedmedicine.org/recent-developments-and-
recurring-dilemmas-in-cancer-screening-colon-lung-thyroid/)

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xpda
Different cancers are different. Skin cancer, both basal cell and melanoma, is
usually caused by the sun. Other cancers have a very strong genetic
correlation. This study did not consider the most common cancer in men,
prostate cancer, or breast cancer. It's interesting that random cell division
is such a strong factor in cancer, but it is completely incorrect to say that
luck has a bigger effect than behavior for all types of cancer.

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mojoe
This is an excellent comment, but I want to point out that getting a cancer
that has a strong genetic correlation is still "luck" rather than "behavior"
from the perspective of a cancer patient.

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lukifer
The tricky thing with correlation is that behavior can still act as a "middle-
man" for genetic correlation. For instance, a genetic susceptibility to
addictive behavior could lead to higher rates of smoking, and therefore lung
cancer. (While some of the more obvious factors might be corrected for,
there's no way that all of them would be.)

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thanatosmin
There are a variety of basic errors in the interpretation of this study:

[http://ameyer.me/science/2015/01/02/vogel.html](http://ameyer.me/science/2015/01/02/vogel.html)

~~~
thanatosmin
The tl;dr; version: this 65% number comes from a correlation coefficient on a
log-log plot, which means the correlation coefficient has nothing to do with
the actual fraction of cancer cases one can attribute to stem cell division
numbers.

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6thSigma
This is interesting, but dangerous. Smokers make up 90% of lung cancer deaths
[1]. At some point you have to acknowledge that smoking definitely does
something to influence lung cancer.

[1] [http://www.lung.org/stop-smoking/about-smoking/health-
effect...](http://www.lung.org/stop-smoking/about-smoking/health-
effects/smoking.html)

~~~
cpncrunch
Also, exercise reduces colon cancer risk by 40-50% and breast cancer risk by
30-40%. Then there are other risk factors such as poor diet, insufficient
vitamin D, etc. Overall it seems highly unlikely that cancer is mostly "bad
luck".

[http://www.cancer.net/navigating-cancer-care/prevention-
and-...](http://www.cancer.net/navigating-cancer-care/prevention-and-healthy-
living/physical-activity/physical-activity-and-cancer-risk)

~~~
a_c_s
50% of what though? If you have 1 in a million chance, increasing that to 1.5
in a million isn't a big change. If "bad luck" afflicted 1 in 100,000 then
then bad luck would still have a much bigger effect, despite lifestyle changes
clearly being significant.

(These numbers totally made up)

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maj0rhn
The Bloomberg article mis-interprets the scientific article.

In effect, the scientific article shows how we could predict which tissues are
most likely to become cancerous if we had no population statistics on cancer.
That is, we could look at the rate of cell divisions in a tissue and say "Oh
yeah, divisions occur frequently here, so there are going to be more cancers
in this particular type of tissue."

The scientific article does NOT say that the cancer which has arisen in random
person X is mostly due to "bad luck" in person X. If person X smokes 4 packs
of cigarettes per day, the person's risk of lung cancer is certainly affected.
Of course, there is still some element of luck (not every heavy smoker gets
lung cancer), but you can think of it like using loaded dice at the time of
each DNA replication... loaded dice don't turn up snake eyes every time, but
they certainly change the odds, and if you were playing craps there is no way
you would want to use loaded dice.

My reaction to the scientific article is... yawn. The result could have been
predicted. Cancer is a disease of DNA replication. It makes sense that
clinical problems arising from DNA replication would occur most often in
places having the most DNA replication events. But it's nice to have
experimental verification.

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noipv4
We pin-pointed DNA double-strand breaks using sequencing, and found very high
correlation with genes damaged by cancer. For e.g. the "ERG" gene which fuses
with TMPRSS2 in prostate cancer was one of the genes in our list.
[http://www.nature.com/nmeth/journal/v10/n4/carousel/nmeth.24...](http://www.nature.com/nmeth/journal/v10/n4/carousel/nmeth.2408-F4.jpg)

More research should reveal that it's more than just pure luck :)

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goalo
Immune system kills spontaneous blood cancer cells every day -
[http://www.medicalnewstoday.com/articles/272092.php](http://www.medicalnewstoday.com/articles/272092.php)

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UhUhUhUh
Mutations do happen during replication. But is it random? How about underlying
mechanisms involving telomeres or histones? Or something else.

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bitwize
That's just what _they_ want you to believe. They being Corporate America who
profit enormously when you eat their processed foods, smoke their cigarettes,
and take their drugs. Cancer is mainly caused by environmental toxins, so if
you don't want to get cancer you have to detox: eat only raw paleo or vegan,
cleanse with lemon juice or unsweetened tea four times a week, and for God's
sakes man, DON'T BREATHE THE AIR!!!

