Breast cancer

In New Zealand, up to nine women are diagnosed with breast cancer every day. Breast cancer, which can occur in men and women, starts as a harmful growth in breast tissue. There are different types and stages of breast cancer which is determined based on the location of the cancer, how it grows, and the severity of the growth. Breast cancer can spread to other parts of the body, such as the lymph glands, bones, and liver.

According to the Breast Cancer Foundation, 5-10% of breast cancers are hereditary. If you have close relatives that have had breast or ovarian cancer, you may be able to get a genetic assessment to find out your level of inherited risk.

Breast cancer is not common in women under the age of 50. The Breast Cancer Foundation reports that 70% of women diagnosed with breast cancer are over 50. While breast cancer is mainly found in women, about 1% of cases will affect men.

Who is at risk?

There are some factors that put people at a higher risk of developing breast cancer. These risks include:

  • A strong family history of breast and/or ovarian cancer
  • A previous breast cancer diagnosis or history of breast issues
  • Being of Māori or Pasifika descent – Māori women are 35% more likely to develop breast cancer than non-Māori
  • A longer hormonal history – research shows links between the length of time oestrogen is produced and the development of breast cancer
  • Inheriting a faulty gene
  • Radiation exposure
  • Dense breasts
  • Ageing

Checking yourself

The Breast Cancer Foundation recommends getting to know what is normal for your breasts so you can notice when there are changes. For information on how to check yourself, look on their website. When checking yourself, you should look out for:

  • Changes in the appearance of your skin, nipple, or breast
  • Dimpling or puckering on the breast
  • Newly inverted nipples
  • Reddening or a rash on the skin
  • Discharge from the nipple
  • New lumps or thickened tissue
  • Unusual pain that won’t go away

If you notice any of these symptoms, you should see your doctor.


In New Zealand, breast screening or mammograms are free and recommended every two years for women aged 45 to 69. This will be progressively increasing to women aged 74. You can still pay for a mammogram outside of this age if you feel you need to. Getting regular mammograms can improve your chances of finding breast cancer early, since a mammogram can pick up a growth before you can feel it. If your mammogram shows a growth or something unusual, you will be asked to complete more tests such as an ultrasound or biopsy.


Breast cancer treatment is decided with you and a specialised team to find the best option for you. A multidisciplinary team may include your GP, a breast surgeon, a pathologist, an oncologist, a dietitian, and therapists. Some options for treatment that may be discussed with your team include surgery, chemotherapy, radiation therapy, hormonal therapy, and targeted therapy. It is important that you understand all of the options available to you and work with your team to find one that is best for you.


While breast cancer cannot be completely prevented, there are some ways to limit your risk.

Maintain a healthy weight after menopause: Breast cancer has been linked to the production of oestrogen. After menopause, oestrogen is produced in fat tissue instead of in the ovaries, meaning that women who are overweight after menopause have higher levels of oestrogen compared to a post-menopausal woman of a healthy weight. Eating healthily and getting regular exercise can help to maintain a healthy weight.

Regular exercise: Studies have shown that getting regular exercise can decrease your chances of developing breast cancer. The Breast Cancer Foundation claims that people who exercise for 3-4 hours a week can reduce their risk of breast cancer by 20-30%.

Limit alcohol intake: Consuming alcohol changes the way your body metabolises oestrogen, meaning that drinking alcohol can raise your blood oestrogen levels. The Cancer society takes a strong position on alcohol use in relation to cancer, which can be read here.  

Hormone Replacement Therapy: Commonly used to treat moderate to severe symptoms of menopause, hormone replacement therapy (HRT) may increase the risk of breast cancer development in women. Studies have shown that the longer you use HRT, the higher the risk of breast cancer. For this reason, HRT users are recommended the lowest dose necessary for the shortest time possible. Extended use of HRT for more than 5 years can double the risk of breast cancer.


The Breast Cancer Foundation and Breast Cancer Aotearoa Coalition (BCAC) offer many areas of support for patients and family. Free counselling and rehabilitation is offered through the Breast Cancer Foundation, and patient information events can offer more information on breast health and treatment. Support for families can be found on the Breast Cancer Foundation and BCAC websites. Support for Māori and Pasifika breast cancer patients can be found here.

Websites of interest