Women left in the dark

One in 10 Kiwi women has dense breast tissue and a higher cancer risk but there’s a gap in screening, writes Tom Pullar-Strecker.

Women aren’t being told when they are at higher risk of breast cancer because the Ministry of Health doesn’t see any point in making them ‘‘anxious’’.

Research suggests women with dense breasts are four to six times more at risk of getting breast cancer.

It is also more likely that the cancer will go undetected.

When viewed on a mammogram, dense breast tissue appears as white – which means it is difficult to see through, and to read the results clearly.

BreastScreen Aotearoa clinical leader Dr Marli Gregory said information on individual women’s breast density was not collected during screening, and would not be communicated to women.

She added that there was ‘‘insufficient evidence’’ to recommend additional tests for women with dense breasts.

‘‘The harms of extra imaging, such as causing anxiety, unnecessary needle biopsies, over-diagnosis and cost, are likely to outweigh the benefits,’’ she said.

But she opened the door to change, saying evidence on breast density was ‘‘regularly reviewed’’ by BreastScreen Aotearoa.

‘‘There are large, well-designed trials under way in Europe looking at reductions in breast cancer mortality for organised screening programmes from different additional imaging protocols, and we are awaiting the results with

The harms of extra imaging, such as causing anxiety, unnecessary needle biopsies, over diagnosis and cost, are likely to outweigh the benefits. Marli Gregory BreastScreen Aotearoa

interest.’’

Chief executive Ralph Highnam estimated about 10 per cent of Kiwi women had dense breast tissue.

It was important that confidence in mammogram screening was not undermined, he said.

‘‘But breast cancer screening organisations are now aware of breast density globally and they should be looking very seriously at how to improve screening programmes based on the knowledge that is out there.’’ Volpara Health Technologies, a Wellingtonbased company set up by former Oxford University academics, has led the world in developing a fully automated tool to assess breast density.

Its software is being used by about 100 of the 9000 screening clinics in the US, where 27 state governments have passed laws that require screening organisations to provide information on breast density to women at risk.

The powerful Food & Drug Administration (FDA) is considering making reporting mandatory across the US.

The purpose would be to help women consider whether they might benefit from extra tests such as ultrasound, MRI scans or 3D digital tomosynthesis.

All of these procedures have some potential to help detect cancers in women with dense breasts at an earlier stage.