[ RadSafe ] Radiation may (not) increase risk in BRCA positive women

[Brad Keck]

The article, which may be found at the website of the British Medical Journal, is an interesting read.  The principal questions I have involve – and perhaps one of the authors will care to comment –  the method used to avoid selection bias and statistical significance.  It seems entirely likely that the women in the study  - all BRCA positive -  who eventually developed a cancer would have been likely to have received more medical attention, hence more diagnostic x-rays, etc., so there is an inherent bias in the study group in that the eventuality of cancer may be related to the increased medical atention, rather than any causality.  The authors allude to correcting for this, but do not explain their rationale – this is a key point on principle.
Secondly,   this is a statistically noisy study.  50 of 57 odds ratios shown encompass unity, and even those that do not are pretty close.  The importance of statistical significance here should not be understated, as the headlines in the popular press most certainly do.  
While it would be an important finding if such a subgroup as this really has a unique susceptibility to radiation, this paper does not make the case to conclude this, in  my view; and is in contrast to similar studies as the authors correctly note.  
Bradly D. Keck, Ph.D., CHP  


On Sep 10, 2012, at 07:47 AM, Colette Tremblay <Colette.Tremblay at ssp.ulaval.ca> wrote:


According to the article, mammograms would increase breast cancer only in a subgroup of young women: those who carry a BRCA1 or BRCA2 mutation. Since these mutations make a woman more susceptible to develop breast cancer, it seems quite logical that these same cells would be less resistant to radiation. Maybe their DNA repair mechanisms are less efficient. 

Colette Tremblay, 
Radiation Safety Officer
Service de sécurité et de prévention
2325, rue de la Vie-Étudiante, local 1533
Pavillon Ernest-Lemieux - Université Laval
Québec (Québec)  G1V 0B1
418 656-2131, poste 2893


-----Message d'origine-----
De : radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] De la part de Howard Long
Envoyé : 7 septembre 2012 23:36
À : The International Radiation Protection (Health Physics) MailingList
Cc : radsafe at agni.phys.iit.edu
Objet : Re: [ RadSafe ] Radiation may increase OR DECREASE breast-cancer risk in young women

How Much Radiation?!!
Hormesis, stimulation of body defenses, clearly LESSENS the risk of cance in low dose, as shown in experiments of Feinendigan, Pollycove, Scott and others!

Even in the bomb studies, Breast cancer was LESS THAN EXPECTED at under 10 Rads.
Howard Long, (family doctor, epidemiologist)

On Sep 6, 2012, at 10:14 PM, ROY HERREN <royherren2005 at yahoo.com> wrote:

> http://seattletimes.com/html/health/2019087004_breastcancer07.html
> Radiation may increase breast-cancer risk in young women Roy Herren 
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