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.
When breast cancer spreads to other parts of the body, typically the brain, bones, liver and lungs, it is still considered breast cancer as the tumour is genetically the same as the originating tumour in the breast.
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.
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.
Thanks to research treatments for metastatic breast cancer have progressed, however, they are not effective for all women with this stage of the disease. Most current treatments are intended to control and growth and spread of the cancer and prolong life.
^Global Status of Advanced / Metastatic Breast Cancer, 2005-2015 Decade Report, March 2016