Background: Mammograms are useful in identifying early breast cancers before they become palpable, but they can also give us information about mammographic density, a strong risk factor for breast cancer. Mammographic density has been suggested as a biomarker for breast cancer risk and is currently being used as a surrogate endpoint for breast cancer in several cancer prevention trials.
Material and methods: This article summarises the rationale for using mammographic density as a surrogate endpoint for breast cancer, with an emphasis on the results that have been published over the last decade.
Results: Mammographic density not only represents a strong risk factor for breast cancer, it is also modifiable. Mammograms are non-invasive and mammographic density is readily assessed using computer-assisted methods.
Interpretation: The ultimate question that remains to be answered is whether a change in mammographic density translates to a change in breast cancer risk. This question could easily be addressed in the Norwegian Breast Cancer Screening Programme if participants were asked the necessary questions when attending the screening programme.