What is HER2-Positive Breast Cancer?
HER2 positive breast cancer is a type of breast cancer that tests positive for a protein called human epidermal growth factor receptor 2 (HER2). An excess amount of HER2 promotes the growth of this type of breast cancer.
HER2-positive breast cancer tends to be a faster growing form of breast cancer compared with HER2 negative disease. Despite this, it often responds very well to available treatments. HER2-positive breast cancer can either be hormone-receptor (HR) positive or negative.
How Common is HER2-Positive Breast Cancer?
Around 15-20% of all breast cancers are HER2-positive. It’s more common for younger, pre-menopausal, women to be diagnosed with HER2-positive disease.
What are the Symptoms of HER2-Positive Breast Cancer?
Some patients diagnosed with HER2-positive breast cancer may not present with any symptoms. When symptoms are present, they may include:
- A new lump in the breast, armpit area or around the collarbone
- Thickening or hardening in the breast
- A change in breast size or shape
- Changes to the nipple, such as sores or crusting, an ulcer or inverted nipple
- Clear or bloody nipple discharge
- Changes to the skin including redness, puckering, or dimpling (an ‘orange peel’ appearance)
- Breast tenderness or pain
If the cancer has progressed to the metastatic stage, further symptoms may be present dependent on where the cancer has spread. Learn more about metastatic breast cancer here.
How is HER2-Positive Breast Cancer Diagnosed?
HER2-positive breast cancer will be diagnosed in the same way as most other breast cancers. This includes a mammogram or other scans. A biopsy will most likely be ordered to determine the HER2 status of the cancer. This will help the treatment team plan cancer treatment. Sometimes the HER2 test is done on the cancer after it has been surgically removed.
If the breast cancer has spread and metastasised, further tests may be required to determine the size and location of the metastatic breast cancer.
How is HER2-Positive Breast Cancer Treated?
HER2-positive breast cancer is treated using a HER2 targeted therapy. The most common HER2 targeted therapy available in Australia and New Zealand is trastuzumab (Herceptin). The Breast Cancer Trials HERA clinical trial found Trastuzumab significantly reduced the likelihood of HER2-positive breast cancer returning.
For women with HER2 positive metastatic breast cancer, trastuzumab may be given with other treatments, or other HER2 targeted treatments used, and will continue so long as the benefit to the patient outweighs the side effects.
HER2-positive breast cancer patients may also receive a combination of treatments including surgery, radiation, chemotherapy as well as targeted treatments. If the tumour is also HR positive, hormone blocking treatments may also be prescribed.
What are my chances of Survival (prognosis) if I am Diagnosed with HER2-Positive Breast Cancer?
HER2-positive breast cancer is a faster growing form of the disease. However, thanks to targeted treatments like trastuzumab (Herceptin), survival rates have improved substantially.
Your age, stage of disease and tumour type has the greatest impact on your chance of survival. Those diagnosed with stage one breast cancer have a 96% chance of surviving five years post diagnosis, while those diagnosed with HER2-positive stage four breast cancer have over 50% chance of surviving five years after diagnosis of metastatic disease.
Overall, the five-year survival rate for women diagnosed with breast cancer is 91.5%, and 86.4% for men