Breast density

A woman’s breast is made up of both fatty tissue and fibroglandular tissue (non-fatty) tissue. On a mammogram, fatty tissue appears black while the remaining breast tissue appears white or ‘dense’.

The amount of fibroglandular tissue (white areas) on a mammogram is referred to as breast density. Dense breasts are common and normal occurring in about 40% of women over 40 years or age.

As breast cancers also appear as white areas on a mammogram, high breast density reduces the ability to see breast cancers. Despite this, screening mammography is still the best population based breast cancer screening test for women aged 50 to 74, including those with dense breasts.

an example female breast density - least dense Least dense

an example female breast density - less dense Less dense

an example female breast density - more dense More dense

an example female breast density - most dense Most dense

You can read more about breast density at Cancer Australia.