How Contrast-Enhanced Mammography (CEM) could help detect breast cancer earlier in women with dense breasts

Breast density is a challenging factor in breast cancer screening effectiveness. If your breasts are dense, it may be difficult to interpret your mammogram. Tumours and other breast changes that need investigation appear white on a mammogram, but so does dense breast tissue. This means concerning changes, or cancer, can be missed in women with very dense breasts.

When mammograms miss cancers in dense breasts, women are more likely to be diagnosed only after symptoms appear. Breast cancers diagnosed this way are three times more likely to be a late-stage (stage 3 or 4) diagnosis, reducing opportunities for successful treatment and cure.

Approximately 40% of screened women have dense breasts and 8–10% have extremely dense breasts. Breast density is more common in younger women under the age of 45 and there’s also evidence that wāhine Māori may have higher breast density than other ethnicities in Aotearoa.

Contrast-Enhanced Mammography (CEM) is a type of breast imaging that uses both a standard mammogram and a special dye injected into the bloodstream. The dye helps highlight extra blood vessels that cancers create as they grow, making tumours easier to see.

Research has shown that there is a nearly threefold improvement in detecting cancer in women with dense breast tissue using CEM. Studies have also found that CEM performs similarly to MRI in detecting breast cancer, while being faster, more accessible and less expensive. A CEM scan usually takes around 7–10 minutes, compared to 10-30 minutes for a MRI.

Potential benefits of CEM for women in Aotearoa are:

• Quicker diagnosis and treatment: CEM in the screening programme would help find more cancers earlier, including cancers that are diagnosed in between mammograms and eventually save more lives down the track.

• A more patient-friendly option: CEM can be a better fit for women who find MRI scans uncomfortable due to claustrophobia or anxiety, or for those who have implanted medical devices or health conditions that make MRI unsuitable.

International evidence, guidelines, and regulatory changes all point toward CEM as an increasingly important tool in early detection of breast cancer.

Currently, CEM is only available at a small number of specialist clinics in New Zealand, in Auckland and Wellington. It is not available through the public health system.

The question is not whether there should be wider availability of CEM, but how it should be implemented into the public system and who would most benefit.

We’d like to see BreastScreen Aotearoa explore the use of technologies like this, so more women can get an early diagnosis. Breast cancers found at stage 1 or 2 have a 92% survival rate, and we want more New Zealanders diagnosed with breast cancer to live long, fulfilling lives with the ones they love. Changes to screening, like expanding imaging to technologies like contrast enhanced mammography, will bring us closer to our vision of zero deaths from breast cancer.

If you want to find out if CEM is an option for you, speak with your GP or specialist, who can consider your medical history, and advise on the most appropriate option for your situation.