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Re: Does CT lung cancer screening LOWER lung cancer risk?
Howard,
I would say that since the differences between actual
and expected cancers is so small, neither a
detrimental or beneficial effect can be demonstrated.
I would say stop smoking would provide a greater
benefit than any supposed CT radiation dosage. As a
physician, wouldn't you agree?
--- Howard Long <hflong@pacbell.net> wrote:
> "4,687 non-leukemic cancer deaths occurred in 50,115
> [exposed] survivors
> where we estimated 4,306 would have occurred, had
> they not been exposed [to
> 1 to 10 cSv or rads]." (ref below). Indeed, that
> would suggest a slight
> INCREASE in cancer deaths from CT, (c 1 rad).
>
> However, the small difference (8%) might be
> explained by many variables.
>
> Mostly I doubt the conclusion because it is
> inconsistent with other data:
> The Breast Cancer Incidence Among Atomic Bomb
> Survivors (Land CE, McGrgor
> DH, JNatl Cancer Inst 1979 Jan;62(1):17-21 table 2
> shows "average tissue
> dose, rads Observed 109 vs Expected 127.8 p,0.0001",
> but broken down,
> rads 1-9, Observed 34 breast cancers, Expected 42.3
> breast cancers!
>
> Thus for that dosage, there is evidence that 1-9 rad
> acute exposure may
> LOWER breast cancer risk. I abandoned design for a
> study using mammography
> and CT
> because the 1 rad acute from the CT would lower the
> power to detect
> significant differences, since it would have much
> the same benefit as the
> exposure (no good placebo). This is much the same
> problem as drug companies
> are having with placebo in anti depressants (Wall St
> Journal, 6/18/04).
>
> I think CT may LOWER lung cancer risk.
>
> Howard Long
>
> ----- Original Message -----
> From: "John Jacobus" <crispy_bird@YAHOO.COM>
> To: "Keith Welch" <welch@jlab.org>;
> <radsafe@list.vanderbilt.edu>
> Sent: Friday, June 18, 2004 1:43 PM
> Subject: Re: Article: Lung cancer screening raises
> lung cancer risk
>
>
> > The Radiation Effects Research Foundation show 63
> > deaths (2% of 3391 cancer deaths) between 5 mSv
> and
> > 200 mSv
> >
> http://www.rerf.or.jp/eigo/radefx/late/cancrisk.htm
> >
> > Of course I have not read any of the reports which
> > might have more current information. However, it
> > appears to be a bit of data mining
> (word-smithing?) to
> > enhance the risk value.
> >
> > Keith, the HPS position paper I think you are
> > referring to is at
> > http://hps.org/documents/radiationrisk.pdf
> >
> > --- Keith Welch <welch@jlab.org> wrote:
> > > Is this really right? Are the bomb survivor
> > > statistics correct? How does the cancer risk in
> the
> > > atomic bomb cohort reconcile with the HPS
> position
> > > paper on "radiation risk in perspective" which
> > > states that quantitative risk estimates should
> not
> > > be used below 10 rem? (coincidentally, it seems
> > > that position paper is no longer on the HPS
> website.
> > > Is it under revision?)
> > >
> > > "For example, 10 low-dose CT lung screening
> > > examinations would produce lung doses in the
> range
> > > of
> > > 25 to 90 mGy," he wrote. "Among approximately
> 30,000
> > > individuals in the cancer incidence cohort of
> atomic
> > > bomb survivors who received doses between 5 and
> 100
> > > mSv (mean dose, 29 mSv), there was a
> statistically
> > > significant increase in cancer risk (77 excess
> > > cancers, p = 0.05) compared to that in the
> control
> > > population."
> > >
> > >
> > > Keith Welch
> > >
> > >
> >
>
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> >
> > =====
> > +++++++++++++++++++
> > "To be persuasive, we must be believable,
> > To be believable, we must be credible,
> > To be credible, we must be truthful."
> > Edward R. Murrow
> >
> > -- John
> > John Jacobus, MS
> > Certified Health Physicist
> > e-mail: crispy_bird@yahoo.com
> >
> >
> >
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=====
+++++++++++++++++++
"To be persuasive, we must be believable,
To be believable, we must be credible,
To be credible, we must be truthful."
Edward R. Murrow
-- John
John Jacobus, MS
Certified Health Physicist
e-mail: crispy_bird@yahoo.com
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