How the Breast Cancer Foundation National Register could help improve care for people with DCIS

Being told you have ductal carcinoma in situ (DCIS) can be confusing. The word "carcinoma" may make people think they have invasive breast cancer. DCIS is different.

DCIS is the earliest form of breast cancer, when abnormal cells are contained within the breast’s milk ducts and have not spread into the surrounding breast tissue. Because the abnormal cells haven’t grown outside the milk ducts, DCIS is known as a non-invasive breast cancer.

Treatment for DCIS therefore aims to reduce the chance of DCIS developing into invasive breast cancer or returning. This might include surgery (such as a lumpectomy or mastectomy), radiotherapy, or hormone-blocking medication.

Because doctors cannot yet reliably tell who is at higher vs lower risk, treatment is offered to everyone diagnosed to give them the best chance of preventing breast cancer in the future. This means that while some people receive treatment for DCIS that could have become invasive or returned, others may have been at very low risk of this occurring – and received treatment anyway.

Research using data from Te Rēhita Mate Ūtaetae - Breast Cancer Foundation National Register is aiming to change that.

Current treatments for DCIS are highly effective but can have lasting physical and emotional impacts. Surgery can change the appearance of the breast, while radiotherapy and hormone therapy can cause side effects. Lasting effects of treatment can also have great emotional impact.

This is why research aimed at identifying which cases of DCIS are at greater risk of developing into invasive breast cancer or returning is so important. It has the potential to reduce unnecessary treatment while ensuring people at greatest risk receive the treatment they need.

Qian Chen is a researcher at the University of Auckland whose work focuses on DCIS. Her research uses Register data to investigate patterns of care and clinical outcomes of women with DCIS in Aotearoa. Qian also works for the Register as an analyst, so knows the value of the data it holds.

“The Register is highly important as it is used by researchers to deliver real impact for patients and to clinicians. Each time I analyse a piece of data in the Register I’m very grateful for each anonymised data point – I know it’s a taonga (treasure) and by combining them and aggregating them, my research can help to inform better clinical practice”.

“As an epidemiologist, I work with data on a population scale to generate evidence that can inform clinical guidelines and support clinicians in making treatment decisions with their patients. The Register is so important, as it provides this depth of data that can have real-world impacts. Publishing these findings at international conferences and journals brings evidence from Aotearoa to a wider audience, raises the visibility of New Zealand breast cancer research, and encourages greater national and international collaboration.”

Finding better ways to identify who is most at risk will help people receive the care they need while avoiding unnecessary treatment wherever possible.

About Te Rēhita Mate Ūtaetae - Breast Cancer Foundation National Register

Te Rēhita Mate Ūtaetae - Breast Cancer Foundation National Register, holds data gifted by over 60,000 breast cancer patients across Aotearoa.

This data is used for research, to audit care, to help plan breast cancer services, and to identify where further progress is needed to improve the lives of everyone affected by breast cancer, now and in the future. If you’ve been diagnosed with breast cancer, read more on the Register’s website to find out how the information about your diagnosis and treatment is making a difference.