[ RadSafe ] Re: Radiation Hormesis

Steven Dapra sjd at swcp.com
Fri Dec 28 18:45:01 CST 2007

December 28

         This introduces an interesting point which leads us into the 
philosophy of regulation.  Some people have pre-dispositions to get cancer 
--- it runs in their families.  Should we regulate to accomodate people who 
are likely to contract cancer no matter what?  If the regulators follow the 
ICRP and NCRP risk estimates it would seem that we are doing so.

         Let's back up again and remember that 65 percent of cancer is 
caused by smoking and diet.  A possible ten percent is caused by 
infections, seven percent by reproductive and sexual behavior, four percent 
by occupation, three percent by alcohol, and three percent by sunlight and 
radiation.  Medicine and medical practices cause one percent, and one 
percent is miscellaneous causes.  This list is from Doll and Peto, The 
Causes of Cancer: Quantitative Estimates of Avoidable Risks of Cancer in 
the U.S. Today, Oxford University Press; (1981).  I am quoting from a 
reproduction of D&P's figures in Environmental Cancer --- A Political 
Disease by Lichter and Rothman, Yale Univ. Press, (1999); p. 62.  R&L quote 
two other pairs of research writing in 1977 and in 1979, who present 
roughly similar estimates.

         My point?  If people don't want to get cancer the best thing to do 
is stop smoking and eat a proper diet.  Quit worrying about phthalates, 
Alar, and ethylene dibromide.

Steven Dapra

At 03:31 PM 12/28/07 -0800, John R Johnson wrote:
>Steven et al
>I've enjoyed this discussion, but I haven't seen any indication that the 
>risk of cancer to individuals depends on an individual's genes. The ICRP 
>and NCRP dose vs risk numbers are for the most sensitive individual, not 
>the average.
>John R Johnson, PhD
>4535 West 9th Ave
>Vancouver, B. C.
>V6R 2E2, Canada
>(604) 222-9840
>idias at interchange.ubc.ca
>----- Original Message ----- From: "Steven Dapra" <sjd at swcp.com>
>To: "John Jacobus" <crispy_bird at yahoo.com>; <radsafe at radlab.nl>
>Sent: Friday, December 28, 2007 3:00 PM
>Subject: Re: [ RadSafe ] Re: Radiation Hormesis
>>Dec. 28
>>         To back up a little ways, perhaps we should keep in mind that 
>> even if hormesis were proven to be false that would not mean that low 
>> level exposure to any specific substance (or to radiation) is harmful.
>>         Salutary exposure, harmless exposure, and harmful exposure are 
>> three separate and distinct topics.  I haven't been keeping records, but 
>> I think that too often discussions of whether or not an exposure is 
>> harmless slide off into an argument about hormesis.
>>Steven Dapra
>>At 08:42 AM 12/28/07 -0800, John Jacobus wrote:
>>>If one does not believe there are problems with using small animal 
>>>models (mice and rats) for chemical testing of effects in humans, should 
>>>consider that approximately 80% of the drug responses seen in such 
>>>animals do not lead to effective results in humans.
>>>But the issue is not effects in one species over another.  It has to do 
>>>with safety in humans.  Only about 15% of a regulator ruling is based on 
>>>the science.  The rest is the politics.
>>>Steven Dapra <sjd at swcp.com> wrote:
>>>Dec. 27
>>>Yes, don't we all love those eminent scientists. Okay, enough on
>>>that front.
>>>". . . proof that a substance, which had been recognized as
>>>carcinogenic in animals, actually causes cancer in man would require in
>>>most cases extemely complex and lengthy epidemiologic studies. In many
>>>cases, it may be impossible to obtain such proof because of the complexity
>>>of controls that would be needed for a satisfactory
>>>demonstration. Therefore, the only prudent course of action at the present
>>>state of our knowlege is to assume that chemicals which are carcinogenic in
>>>animals could also be so in man, although the direct demonstration in man
>>>is lacking."
>>>The citation is: Umberto Saffiotti, "The Laboratory Approach to
>>>the Identification of Environmental Carcinogens," in Proceedings of the
>>>Ninth Canadian Cancer Research Conference 1971, edited by P. G. Scholefield
>>>(University of Toronto Press, 1972), pp. 23-26; cited in Federal Register
>>>42:192 (October 4, 1977): 54152. I am quoting from "The Apocalyptics
>>>Cancer and the Big Lie," by Edith Efron (Simon and Schuster, 1984). Efron
>>>quotes Saffiotti on p. 87.
>>>Sure, I'll grant you that was 1971 --- 36 years ago and a lot has
>>>changed since then. Or has it? Are we any closer to knowing *for certain*
>>>whether nor not it is possible to extrapolate from carcinogenicity in
>>>animals to carcinogenicity in humans?
>>>To further complicate matters, according to Efron, cats, dogs,
>>>rats, mice, and hamsters get cancer from 2-acetylaminofluorene; but guinea
>>>pigs, lemmings, and the cotton rat do not. And it goes on and on. See pp.
>>>198-190 of Efron for more examples of selective carcinogenicity. She gives
>>>citations for everything, citing to the scientific literature, or to
>>>government reports on carcinogenicity.
>>>Steven Dapra

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