What is metastatic breast cancer?

Metastatic breast cancer, also known as secondary breast cancer, advanced breast cancer or stage 4 breast cancer, occurs when the tumour spreads beyond the primary site of the breast.
Breast cancer originates in the breast, and can be treated with surgery, radiation, chemotherapy and targeted treatments to eliminate cancer cells from the body.


However, sometimes not every cancer cell is eradicated. They may also survive treatment or escape into the blood stream before treatment starts. It only takes a single cancer cell in the body for it to grow into a tumour and spread to other parts of the body.

Who is at risk of metastatic breast cancer?

Many women diagnosed with secondary breast cancer have already been diagnosed and successfully treated for breast cancer, but for others being diagnosed with metastatic breast cancer may be the first time they’ve known about it.

In developed countries like Australia, around 20-30% of women who have been diagnosed with early stage breast cancer will go on to develop metastatic breast cancer.^ This can sometimes occur more than 10-15 years after the original diagnosis.^

The survival rate of women that have metastatic breast cancer at first diagnosis is alarmingly low, with only 1  in 4 women still alive 5 years after diagnosis.^

How is research helping?

The National Breast cancer Foundation invests in breast cancer research – in 2017 50% of funded research projects focused on metastatic breast cancer thanks to the generosity of the Australian public. Each research project has the potential to bring us closer to zero deaths from breast cancer by 2030.

  • Liquid biopsies: Tumour cells release circulating DNA (ctDNA) into the blood, making a liquid biopsy, or blood sample, a cost-effective and less invasive diagnostic and prognostic tool for determining if cancer has moved beyond the primary site and is spreading to other parts of the body through the blood. A universal biomarker for determining cancer relapse or spread has not yet been discovered, however Professor Kirill Alexandrov from Institute for Molecular Bioscience, University of Queensland is working towards a simple blood test that breast cancer survivors could do at home. Read more here.
  • Nanotechnology: Nanotechnology is being researched for targeted drug delivery, where cancer-detecting nanoparticles are loaded with anticancer drugs that bind to and destroy tumours with minimal damage to healthy tissue and organs. They use less medication and could potentially include time-release doses. It’s an exciting area of research but is still very much in the developmental stage. Read about NBCF-funded Professor Phil Darcy from the Peter MacCallum Cancer Centre who is designing new nanotechnologies that will engage to immune system to eradicate cancer cells. Read more here.



Symptoms of metastatic breast cancer 

Breast cancer can reappear in different parts of the body, affecting different organs. Every woman’s experience of metastatic breast cancer is different and symptoms will depend on where the tumour is located and could develop over weeks or months.

Treatment for metastatic breast cancer 

Most current treatments are intended to control the growth and spread of the cancer and prolong life. These treatments are not effective for all women with this stage of the disease, or could become ineffective over time. Thanks to research, more treatments for metastatic breast cancer are being developed.

^Global Status of Advanced / Metastatic Breast Cancer, 2005-2015 Decade Report, March 2016