Benefits/risks balance of breast cancer screening

Interactive decision-making tool

To form an opinion on breast cancer screening and whether or not to participate, it is meaningful to weigh the expected benefits of screening against the risks to which you are exposed.
This page provides information regarding the benefits/risks ratio of cancer screening based on various participation, effectiveness, and adverse effects assumptions.

Your assumptions

Key assumptions (to be completed or verified before starting the calculations)

Mortality reduction with screening (%):
(clinical studies place this mortality reduction between 0 and 35%)

Proportion of overdiagnosis among screened cancers (in %) :
(clinical studies place the proportion of overdiagnosis between 5 and 50%)

Starting age for screening participation: Age at end of screening:
(these 2 age limits can be modified if there is a need to have a benefit/risk balance for a later entry or earlier exit from screening)

Other assumptions (preset for the situation in England but can be modified if needed)

Women's participation rate in screening (in %) :
(default value of 70% can be modified if needed)

Breast cancer incidence (per 100,000 women)

between 50 and 54 years of age:	between 55 and 59 years of age:	between 60 and 64 years of age:
between 65 and 69 years of age:	between 70 and 74 years of age:
(the above incidences are for England in 2017; they can be modified if needed)

Breast cancer case lethality (in %):
(lethality is the proportion of breast cancers that will lead to death; this value can be modified if needed)

Periodicity of mammograms (screening mammogram every ... years) :

Number of false alarms per 1000 screening mammograms:
(this number of 37 false alarms can be modified if needed)

Benefit/risk balance

The benefit/risk balance shown below corresponds to what is expected in two groups of 1000 women, one of whom participates in screening and the other does not.
The main assumptions made are:
- a reduction in mortality with screening of
- an overdiagnosis rate with screening of
- for the group participating in screening, a start of participation in screening at age 50 and an end of participation at age 70, representing 7 screening mammograms.

The mortality reduction and/or the proportion of overdiagnosis are missing!

Women participating in screening	Women not participating	Screening outcomes
			For one life saved:

Details of calculations

You must first fill in your mortality reduction and overdiagnostics frequency assumptions!

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