Studies of Cancer Risk

[Holloway3@aol.com]

It is interesting that there are dozens upon dozens of organizations dedicated
to explaining and (perhaps) reducing the very small risk that is associated
with the use of radioactive materials while ignoring the much greater and more
important risks associated with common things such as smoking, lack of
exercise, abuse of alcohol etc.  To put things into perspective, I often ask
people to use their own personal experience as a yardstick to measure risk.  I
often ask the question: How  many people do you know who have died or been
injured by these common risks as compared to radiation?  Most people answer
that they know many who have died from abuse of alcohol, smoking etc, and that
this number is far greater than the number of people harmed by radiation.  I
conclude that it is a risk that is not worth worrying about for 99.9% of the
population.  

Something else must be involved in the creation of these organizations other
than a rational approach to risk reduction.  I don't know of any organizations
involved in protecting people against shark attacks, lightning strikes,
rattlesnake bites or bites
from Gila monsters.  I suspect that a good case could be made that the risks
of these unusual events are in some cases greater than the risk from
radiation, at least for the general public.  

Mr. Faber mentions some studies that allege  increased risk.  I have not read
the studies he mentions, but sometimes these studies have less evidence than
they claim.  I recently read a study by Wing et. al. on radiation workers at
Oak Ridge.  He evaluated 12 death rates from 12 different cancers and claimed
that radiation was connected to an elevated rate for one of them.  He did not
attempt to explain the lower than normal rate for some of the 12 cancers,
which were in some cases depressed below normal almost as much as the one type
that was elevated.  My view of his numbers is that the evidence was ambiguous
and not conclusive.  If in fact the radiation exposure had no effect on any
type of cancer, then the expected result for all 12 types would be that the
measured mortality rates would fall randomly both above and below the expected
death rates.  That is approximately what happened with the death rate for 7
types being below the expected rate and the death rate for 5 types being above
the expected rate.  Wing's "spin" on the results would have done a politician
proud.  He claimed that he found evidence that one type of cancer was elevated
due to radiation exposure and calculated the risk as a function of dose.
However, a recalculation using Wing's methods, in a thesis by a Berkeley
graduate student,  produced a contrary result and concluded that if two
cancers normally associated with smoking were thrown out, that there were no
excess deaths from cancer due to low level radiation exposure.  These two
particular cases had relatively high doses and apparently skewed some of the
curve fitting.  

The most important conclusion that can be drawn from the data above was that
the mortality due to cancer for Oak Ridge workers is less than that of the
general population for cancer as a whole (i.e. not dividing it into different
types).  Only by straining mightily and selecting a small part of the data
(while ignoring other small parts), can any contrary argument be made.  What
of the depressed rates for the 7 types of cancer?  Wing did not explain the
depressed rates, but most likely it could be due just to random statistical
fluctuations.  If so, that suggests the possibility that the elevated rates
can be explained in the same way.  If one is to make arguments based on slight
deviations from the norm, it is not reasonable to base the arguments on only
the deviations that have a positive sign, but the whole data set should be
considered.  I don't know how typical Wing's methods are, but some skepticism
is in order, it seems.  It is not being defensive to call junk science by its
rightful name. 



                                                          Robert Holloway
                                                          Nevada Technical
Associates, Inc.
                                                          http://www.ntanet.ne
t/publicinfo.html








<< please Melissa bear with me while I prolong this "thread" one more 
      time!
      
      It's not so much defensiveness as being sick and tired of hearing the 
      risks exaggerated.  >>