[ RadSafe ] What does it mean to say that something causes 16% ofcancers?

[Brennan, Mike (DOH)]

Thanks for bringing this to our attention, Cary.  I can think of a
number of people I would like to have read (and understand) this.  

My feeling is that when discussing something like PAFs, the numbers
should be multiples of 10, and everything to the right of the decimal
should be replaced by "ish".  I am skeptical about the value of "16.1%",
but I am fairly comfortable with "20-ish%".

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Cary Renquist
Sent: Thursday, May 10, 2012 12:28 PM
To: radsafe at agni.phys.iit.edu
Subject: [ RadSafe ] What does it mean to say that something causes 16%
ofcancers?

Nice short article on cancer statistics...

What does it mean to say that something causes 16% of cancers? | Not
Exactly Rocket Science | Discover Magazine 
http://j.mp/IWBpG6


The numbers aren't about assigning blame.

For a start, PAFs don't necessarily add up. Many causes of cancer
interact with one another. For example, being very fat and being very
inactive can both increase the risk of cancer, but they are obviously
linked. You can't calculate the PAFs for different causes of cancer, and
bung them all into a nice pie chart, because the slices of the pie will
overlap.

Cancers are also complex diseases. Individual tumours arise because of a
number of different genetic mutations that build up over the years,
potentially due to different causes. You can't take a single patient and
assign them to a "radiation" or "infection" or "smoking" bucket. Those
16.1% of cancers that are linked to infections may also have other
"causes". Cancer is more like poverty (caused by a number of events
throughout one's life, some inherited and some not) rather than malaria
(caused by a very specific infection delivered via mosquito).


Cary
--
Cary.renquist at ezag.com
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