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Radiation to the breast is hormetic at 0.15 Gy- feel free delete without reading!
>Date: Wed, 11 Feb 1998 17:48:07 -0400
>Reply-To: Medical Physics Mailing List <MEDPHYS@LISTS.WAYNE.EDU>
>Sender: Medical Physics Listserver <medphys@lists.wayne.edu>
>From: JOHN CAMERON <jrcamero@FACSTAFF.WISC.EDU>
>Subject: Radiation to the breast is hormetic at 0.15 Gy- feel free delete
> without reading!
>To: Multiple recipients of list MEDPHYS <MEDPHYS@LISTS.WAYNE.EDU>
>
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>Dear Colleagues, I haven't read the NCRP Report No. 85 but I am somewhat
>familiar with the Canadian study of breast cancer reported by Miller et al
>in the N. Engl. J. Medicine 1989: 321; 1285-1289. That shows data to
>indicate an increase of breast cancer for doses at 0.35 and 0.55 Gy.with a
>RR of 1.2/Gy However at 0.15 Gy the breast cancer incidence is reduced
>about 35% from the unirradiated controls. It is statistically significant
>at the 95% confidence level. The breast cancer incidence at 0.25 Gy is a
>lower than for the controls but only about at one std. dev.
> These data from low level have been excluded from published reports
>because "everyone knows that radiation doesn't reduce cancer."
> The discussion of risks from mammography should mention real data
>rather than base risk on the LNT model which has no support at doses below
>about 0.2 Gy.
> The above data is from an article by Myron Pollycove, MD "THE RISE
>AND FALL OF THE LINEAR NO-THRESHOLD (LNT) THEORY OF RADIATION
>CARCINOGENESIS soon to be published in the Physics & Society News
> Another related article by LE Feinendegen, Victor Bond & Chas.
>Sondhaus LOW LEVEL RADIATION MAY PREVENT CANCER describes four cellular
>mechanisms that are protective against cancer below about 0.2 Gy (acute).
>It will be published in the same issue of P&S News. If you can't wait I
>can provide a pre-print copy of either article by mail. (By the way, the
>data from the last article is the reason that I would be comfortable
>getting up to 1 Gy per year if it didn't exceed 0.1 Gy at any one time. In
>case you saw the summary of Walter Huda's survey recently I submitted the 1
>Gy/y value and gave my reason. - I had no political motivation. )
> It would be fair to explain to women having mammograms that the
>radiation dose is likely to reduce the risk of breast cancer! By the way
>how do medical physicists suggest that radiologists or RTs explain the risk
>from a mammogram (or any other exposure). Last year when my wife asked the
>RT how much radiation she would receive for her mammogram, the RT responded
>"enough to do the job!" When I wrote the radiologist asking for the dose
>from the mammogram and from a lower GI series she had from the same
>radiological group, I never received an answer! (I wasn't concerned - I was
>curious how they would respond.)
> Physicists should consider it part of the physics education of
>radiologists to present information on how to explain radiation to
>patients. If anyone is interested I will send via e-mail my article
>EXPLAINING RADIATION TO PATIENTS submitted to Applied Radiology about a
>month ago.
> A major factor for women to refuse mammograms these days is
>because of the pain from the compression. I notice in the recent AAPM
>Newsletter that the compressional force is 25 to 40 lb. That is not
>trivial. Think of that compression force on any of your delicate tissues!
>I think it would be useful to go back to xeromammograms where such force is
>not necessary and the larger dose to the breast would further reduce the
>risk of breast cancer if it didn't exceed 0.15 Gy!
> It is unscientific to base risk from mammograms on the LNT model no
>matter how you calculate the dose. I wonder how many medical physicists
>believe in the LNT model of radiation carcinogenesis.
>
>Wlad wrote:
>>Still, I tend to like Walter's argument. Here is why. To me, the main
>>reason we calculate the dose to the breast is to assess the risk of
>>inducing cancer as a result of irradiation. Clearly, the probability of
>>inducing cancer scales with the irradiated volume. So, the risk for the
>>woman that got diagnostic (whole breast) dose of 150 mrad will actually be
>>larger than the risk for the woman that got 300 mrad to 1/4 of the breast
>>volume during biopsy procedure. I think both women should know that.
>>Wlad
>
>I think they should be told that there are no data to show any risk at
>these low doses. What data exists from the Canadian study shows a reduction
>of risk! Why scare them with non-existant data! John
>
>
>John R. Cameron, winter home: 2678 SW 14th Dr., Gainesville, FL 32608
>phones : 352/371-9865; Fax 352/371-9866 About May 15, 1998 we go to our
>summer home: 2571 Porter Rd., P.O. Box 405, Lone Rock, WI 53556-0405
> Phones: 608/583-2160; Fax: 608/583-2269 e-mail all year:
>jrcamero@facstaff.wisc.edu
>