RE: Article: Lung cancer screening raises lung cancer risk

["Peter Thomas" <Peter.Thomas@arpansa.gov.au>]

According to Brenner's article he also considered risks to "the female

breast, the esophagus, the liver, the stomach and the thyroid" (p443

under "Other Cancer Sites") but found that "the corresponding estimated

risks for all other organs (the highest risk being that for the stomach)

are at least an order of magnitude lower and, thus, are unlikely to play

any role in risk-benefit analysis" (also p443, column 1 in the "Results"

section.



Several people also queried the statement "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".  This information

comes from the article by Pierce and Preston (Radiation Research 154,

178-186, 2000) in which they discuss risks at "low dose" (below 0.5 Sv).

Table 1 in that article shows 30,524 subjects classified into the 5 to

100 mSv dose range with 4,119 solid cancers, including an estimated

excess of 77.  The paper doesn't contain a fuller description of the

data (tabulation of person-years at risk and significance tests, etc.)

but there is a statement in the section discussing threshold models that

"there is statistically significant risk (P = 0.05, one-sided test) in

the dose range below 0.10 Sv."

The control group are the low dose (< 5 mSv) proximal (within 3 km)

survivors, with Table 1 showing 10,159 subjects and 1,301 solid cancers.

A simple ratio calculation (very unsophisticated I admit) predicts

30,524*1,301/10,159 = 3,909 cancers in the 5 to 100 mSv dose group,

compared to the observed 4,119.  The paper discusses reasons for

excluding the distal (beyond 3 km) survivors from the control group,

they represent 23,493 subjects and 3,230 solid cancers.  Adding them in

gives a control group of 33,652 subjects with 4,531 solid cancers and

the simple ratio predicts 30,524*4,531/33,652 = 4,110 cancers in the 5

to 100 mSv dose group, compared to the observed 4,119.  The main

argument given for ignoring the distal survivors is that their

approximately 5% higher cancer rate than the proximal controls is due to

urban-rural differences.



I should point out again that the 77 excess in the 5 to 100 mSv dose

range is for all solid cancer incidence covering the period 1958-1994.

As far as I am aware, the readily available incidence data from RERF is

that for 1958-1987 (see www.rerf.or.jp).  I imagine a new incidence

report might be in the offing, since we had the updated mortality report

(1950-1997) come out last year and a specific non-cancer mortality

report (1950-1998) come out very recently.



Peter Thomas

Medical Physics Section

ARPANSA



-----Original Message-----

From: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of John Jacobus

Sent: Wednesday, 23 June 2004 3:04 AM

To: TConley@kdhe.state.ks.us; radsafe@list.vanderbilt.edu

Subject: Re: Article: Lung cancer screening raises lung cancer risk



Of course, does frequent CT scanning also increase the

risk of other cancers, such as stomach, liver,

thyroid, etc.?



-- John

John Jacobus, MS

Certified Health Physicist

e-mail:  crispy_bird@yahoo.com



--- TConley@kdhe.state.ks.us wrote:

> The real question is not does CT screening raise or

> lower the risk of lung

> cancer but does it identify lung cancer at an early

> enough stage to be

> cured.

> 

> Thomas A. Conley, RRPT, CHP

> Section Chief, Radiation and Asbestos Control

> Kansas Department of Health and Environment

> Phone: (785) 296-1565

> email: tconley@kdhe.state.ks.us







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