english.prescrire.org > Spotlight > Archives : 2015 > Breast cancer screening and mammography: inform women

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Breast cancer screening and mammography: inform women

Information must be shared with women to help them decide whether or not to take part in breast cancer screening.

In a series of articles published over the past year, Prescrire updated its analysis of the harm-benefit balance of breast cancer screening by mammography.

In France, it is estimated that, overall, for every 1000 woman aged 50, around 72 women are diagnosed with breast cancer over a period of 20 years. In the 10 years following this diagnosis, around 13 of these women die from breast cancer, and 4 from other causes.

It is estimated that for every 1000 women who are screened for 20 years beginning at age 50 (11 sessions in total):

  • anomalies suggesting a cancer are seen around 1000 times (sometimes several times in the same woman), and lead to 150-200 needle aspirations or biopsies;
     
  • breast cancer is discovered in around 15 women outside the screening programme;
     
  • breast cancer is discovered in around 75 women through screening;
     
  • in some of these women, early discovery of the cancer results in less extensive treatment;
     
  • between 0 and 6 women avoid death from breast cancer thanks to screening;
     
  • but at least 19 women are labelled "cancer sufferers" and are needlessly exposed to the adverse effects of cancer treatments (breast surgery, radiation therapy, hormone therapy, chemotherapy), whereas their cancer would have remained asymptomatic had they not been screened.

Information on the extent of these overdiagnoses and the associated excessive treatments should be shared with women, and be taken into account in the decision as to whether or not to participate in screening.

©Prescrire 1 July 2015

"Mammographic screening for breast cancer. Overdiagnosis: an insidious adverse effect of screening" Prescrire Int 2015; 24 (162): 186-191. (Pdf, subscribers only).
Download the full review.
Pdf, subscribers only

For more information:

Prescrire's advice:
Sharing relevant information
with women to help them decide
whether or not to participate
in breast cancer screening
Prescrire Int 2015
24 (162): 190.
Pdf, subscribers only

Mammographic breast cancer
screening. Part I - randomised trials:
uncertain, at best modest, reduction
in deaths from breast cancer
Prescrire Int 2015;
24 (158) : 72-73.
Pdf, subscribers only

Mammographic breast cancer
screening. Part II - non-randomised
comparisons: results similar to
those of randomised trials
Prescrire Int 2015;
24 (159) : 99-102.
Pdf, subscribers only