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mammography screening



	

Monty Charles wrote on August 13, 2000: 



< I have a request for information regarding the justification for 

mammography screening.  I am looking for a scientific explanation 

of national policy on the age range of women for which screening is 

considered beneficial.  The benefits of early detection of breast 

cancer have to be balanced against the possible risk of induced 

cancers in the general population of women being screened.  The 

balance presumably requires an estimate of the radiation risk, the 

age dependence of this risk, and the effectiveness of the screening 

process. 

I would like to know if there is any published rationale for national 

screening policies?

Many thanks

Monty Charles

Dr Monty Charles, Reader in Radiation Physics >



Here is my response:



"Breast cancer (BC) is the most common type of cancer among women in the

Western world. It is estimated that there will be more than 193,000 new BC

cases and more than 40,000 deaths due to this disease in 2001 in the U.S.

alone [1]. 

Numerous multi-national studies [2],[3],[4],[5] have consistently

demonstrated that BC mortality can be reduced by the use of mammography. In

the United States, routine mammographic screening, capable of early

detection of BC, has been identified as an important factor in recent

decreases in breast cancer mortality [6],[7].

The average glandular radiation dose due to mammograhic screening is in the

order of

3 mGy (300 mrad). While current knowledge of radiation effects in humans

does not permit

us to state with absolute certainty that there are no risks of low-level

radiation 

exposure in any person, there are good epidemiological studies that suggest

beneficial health effects of such exposures [8], [9]. 

There is no evidence that the level of radiation dose that results from

mammographic screening increases a risk of cancer induction. In my opinion,

the only risk that a woman 

is facing is the risk that screening will miss detecting her BC. Like with

any other diagnostic procedures there are false negatives...

   

References:

1. Greenlee RT, Hill-Harmon MB, Murray T, Thun M. Cancer Statistics, 2001.

CA A Cancer Journal for Clinicians. 2001; 51 (1): 15-36.

2. Ries LAG; Wingo PA; Miller DS; et al. The Annual Report to the Nation on

the Status of cancer, 1973 - 1997, with a Special Section on Colorectal

Cancer. Cancer. 2000; 88 (10): 2398-2424.

2. Smart CR, Hendrick RE, Ruthledge JH; Smith RA. Benefit of Mammography

Screening in Women Ages 40 to 49 Years: Current Evidence from Randomized

Controlled Trials. Cancer. 1995; 75 (7): 1619-1626.

3. Bjurstam N; Bjorneld L; Duffy S et al. The Gothenburg Breast Cancer

Screening Trial. Cancer. 1997; 80 (11): 2091-2099.

4. Feig S. Increased Benefit from Shorter Screening Mammography Intervals

for Women Ages 40 - 49 Years. Cancer. 1997; 80 (11): 2035-2039.

5. Smith RA. Breast Cancer Screening Among Women Younger Than 50: A Current

Assessment of the Issues. A CA Cancer J for Clinicians. 2000; 50 (5):

312-336.              

6. American Cancer Society (ACS) website: http://www.cancer.org/

7. Ries LAG; Wingo PA; Miller DS; et al. The Annual Report to the Nation on

the Status of cancer, 1973 - 1997, with a Special Section on Colorectal

Cancer. Cancer. 2000; 88 (10): 2398-2424.

[8]Smith PG, Doll R. Mortality from all causes among British Radiologists

Br. J Radiol 1981; 54: pp 187-194 (1981)

[9]Matanoski G: Health effects of low-level radiation in shipyard workers

final report. 471 pages Baltimore, MD, DOE DE-AC02-79 EV10095, (1991). Also:

Matanoski, G Nuclear shipyard worker study (abstract) Radiat. Res. 133,

126-12."



Jodi Strzelczyk

Asst. Professor, Radiological Sciences

University of Colorado Health Sciences Center



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