Mammograms still the best tool to catch breast cancer early

Renewed questions have been raised about the value of mammograms after a Canadian study suggested that it does not reduce the number of deaths from breast cancer.

BCAC chair Libby Burgess says while the latest research is thought-provoking, it should in no way prompt New Zealand women to stop getting their free mammograms every two years through BreastScreen Aotearoa.

The study, published in the British Medical Journal, compared Canadian women who had annual mammograms with those who had a physical examination only and concluded that there was no real difference in the number of breast cancer deaths in the two groups. 

The researchers say these results will not automatically apply to all countries but do suggest a need to review the process of annual breast cancer screenings.

However, Libby says the study conflicts with many other studies that have clearly demonstrated the benefits of mammography in helping to save lives.

“The International Agency for Research on Cancer found that mammograms reduced death from breast cancer by around 35 per cent and I think this is the information that New Zealand women need to hold onto.”

Libby says there are flaws in the Canadian research which used questionable methods to randomise participants and also analysed data gathered on primitive mammogram machines which are not as accurate in identifying tumours.  Some of the radiologists used were inexperienced and the detection rates were well below those of a successful screening programme.

She says the information gathered in the Canadian study is not applicable to the New Zealand context.

“BreastScreen Aotearoa now uses ‘state of the art’ digital mammography, which gives very clear and accurate images meaning tumours are more easily identified,” Libby says.

“All mammograms are read independently by at least two highly trained radiologists. We’re very lucky to have such a high quality screening programme in New Zealand.”

She says mammograms also help to identify tumours early, which gives women a much greater chance of survival.

“It’s important to remember that women who have breast cancer identified by screening are more likely to have their breast cancer identified early which means they often don’t need to undergo as intensive or arduous a treatment programme as other women. 

“New Zealand data has shown that screen detected breast cancers are more likely to only need a lumpectomy rather than a mastectomy and are less likely to need chemotherapy to kill the cancer. These things have a huge impact on women’s lives.”

Libby says while mammographic screening is not perfect, it’s an important tool which should definitely be used.  She says new screening methods are being developed, including 3D breast tomosynthesis, but their effectiveness still needs to be validated.

In the meantime, the best tools women have to detect breast cancer early are mammograms and being ‘breast aware’ or knowing the how your breasts ordinarily look and feel and acting immediately when you notice any changes.

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