This article discusses how high mammographic breast density lowers the sensitivity of breast cancer screening and increases breast cancer risk.

Introduction: High mammographic breast density is one of the strongest independent risk factors for the development of breast cancer. It is estimated that over 40% of Australian women
aged forty to sixty-five years have high mammographic breast density, and these women are two to six times more likely to get breast cancer than those with low mammographic breast density. Reductions in breast density significantly reduce breast cancer risk. For example, using tamoxifen to lower mammographic breast density by greater than 10% translates to a greater than 60% decrease in breast cancer risk.

In Australia identifying women with high mammographic breast density is not yet routine; only some private radiology services and BreastScreen WA currently report breast density as part of their
service. However, BreastScreen Australia is currently investigating how to incorporate this information into their reporting procedures.

Technological advances have often driven our understanding of disease and lead to significant improvements in healthcare. From the first X-ray in 1895 to today’s positron emission tomography
(PET) scans, medical technology has been evolving. Digital mammography, 3D tomosynthesis and breast density volumetric measurement software (i.e., Quantra™ and Volpara™) have brought together all of the variables necessary to measure, assess and analyse mammographic breast density.7 While there have been
major advances in the treatment of breast cancer in the last thirty years, there has been little change in breast screening.

Conclusion: Internationally, breast screening is undergoing a paradigm shift
and it is only a matter of time before BreastScreen Australia modifies its protocols and starts routinely reporting mammographic breast density.

A woman’s mammographic breast density is a critical piece of health data and a strong breast cancer risk determinant. Given that breast cancer is one of the most common cancers experienced by
women in mid-life, mammographic breast density measurement gives a unique insight into a woman’s risk and how to manage a preventative strategy.

In this new era of breast screening and prevention, it is vital that General Practitioners have an in-depth understanding of the implications of high mammographic breast density, a knowledge of
prevention and treatment options, and an awareness of emerging treatments and how to implement individualised screening regimens.