Breast cancer | Mate pukupuku ūtaetae

Breast cancer (mate pukupuku ūtaetae) is a harmful growth that starts in your breast tissue. It is the most common cancer among New Zealand women, affecting 1 in 9 women over their lifetime.

On average, 9 people in Aotearoa New Zealand, will hear the news today that they have breast cancer. 

Breastscreen Aotearoa(external link) is a national screening programme providing free mammograms to women aged 45 to 69 years, every 2 years. This service helps to catch breast cancer early and save lives. Read more about breast screening.

Men can develop breast cancer, though this is rarer, adding up to about 1% of all breast cancers.

Cancer is caused when some of the cells in our body start to grow out of control. These cells keep multiplying and form a lump called a tumour.

Some breast cancers grow very slowly, while others grow much faster. Breast cancer can spread to the lymph glands and to other parts of the body, such as the bones and liver.

The causes of breast cancer are not clear, but many risk factors are known. The main factors that influence your risk include being female and getting older. Most breast cancers are found in those who are 50 years old or older. Read more about risk factors for breast cancer below.

Breasts undergo changes throughout life. In particular, breasts may become sore, lumpy or swollen during the menstrual cycle. Not all breast lumps are caused by cancer, but some breast changes that may be early signs of cancer include:

• a distinct lump or lumpiness
• thickening of the tissue or skin
• nipple changes, such as skin dimpling
• a blood-stained discharge from one nipple
• an inverted nipple (unless the nipple has always been turned in)
• a rash on a nipple
• a change in breast shape
• a painful area
• a rash or red mark that appears only on your breast.

If you have any of these changes. You don’t necessarily have breast cancer, but you should see your healthcare provider to get your breasts checked.

Most breast cancers begin in the milk ducts (ductal cancers), while a small number start in the milk sacs or lobules (lobular cancers). Within these 2 groups there are different subtypes of breast cancer.

The causes of breast cancer are not clear, but many risk factors are known. The following factors increase your chance of getting breast cancer:

• Being female.
• Getting older (for females).
• Having previously had breast cancer.
• having an increased number of abnormal cells in the milk ducts (atypical hyperplasia). This can be seen in a breast biopsy.
• A family history of breast cancer:
  • This risk can be mild, moderate or high, and depends on the number of relatives affected, whether they are first or second-degree relatives (first-degree are sisters, brothers and parents), and the age of the relative(s) when their breast cancer was found.
• People who have inherited one of the abnormal BRCA genes associated with breast cancer.

Even with a high risk, most people won't develop breast cancer. 

Heredity and breast cancer

About 1 in 20 breast cancers is caused by a faulty breast cancer gene. If yours was caused by such a gene, your doctor can help you decide whether genetic testing would be helpful for your wider family. Find out more about the BRCA gene.

Most women who develop breast cancer have no family history of the disease, so being aware of what to watch out for and having regular mammograms are your best protection.

Read more about breast cancer screening and mammograms.

You can't change your genes, but you can reduce your chance of getting breast cancer by:

• exercising regularly
• limiting alcohol
• breastfeeding, if possible
• talking to your healthcare provider about contraception or menopause treatments that don't use oestrogen.

Being overweight increases risk, and reducing weight reduces risk.

• Be aware of what your breasts look and feel like normally (see video below). If you notice any changes see your healthcare provider.
• Make use of the free breast screening programme in Aotearoa New Zealand. Every woman from 45 to 69 years of age is eligible for free mammograms every 2 years.  
• Ask your healthcare provider whether you need extra screening. It will depend on how many of your relatives have (or had) breast cancer and how old they were when they got it. 

Video: Checked your breasts lately? We'll show you how.

This video may take a few moments to load.

(Breast Cancer Foundation, NZ, 2015)

Breast cancer is diagnosed by a combination of:

• physical examination of your breast tissue
• diagnostic imaging such as mammogram and ultrasound
• diagnostic tests such as biopsy and testing of cell samples.

Your healthcare provider will talk to you about your medical history and symptoms and will do a physical examination. They may arrange more tests or you may be referred directly to a specialist for a mammogram and/or ultrasound scan. 

Further testing may be required including taking a sample of cells from the lump, biopsy or removal of the lump, and laboratory testing on any breast tissue samples. 

Read more about breast cancer diagnosis.

Breast cancer is treated by 4 different methods: surgery, radiation treatment (radiotherapy), chemotherapy; and hormone treatment.

Which treatment or combination of treatments is used depends on the type and size of the breast cancer and whether it has spread, and the age, general health and personal choice of the woman with breast cancer.

Read more about breast cancer treatment.

Video series interviewing people about their personal journey with breast cancer including the signs, symptoms and treatment.

Video: Helena's story

This video may take a few moments to load.

(Breast Cancer Foundation NZ, 2015)

Video: Kat's story

This video may take a few moments to load.

(Breast Cancer Foundation NZ, 2011)

Watch more personal stories(external link)(external link) from the Breast Cancer Foundation NZ.

Video: New Normal Same Cancer - Shona’s Story

This video may take a few moments to load.

(Breast Cancer Foundation NZ, 2021)

Watch more personal stories(external link)(external link) from the Breast Cancer Foundation NZ.

Breast Cancer Foundation(external link) support page
Breast Cancer Support Inc.(external link)(external link) One-on-one calls, support, groups, step by step support pack(external link)(external link) and more.
Personal stories(external link)(external link) (English and Maori) National Screening Unit, NZ
What can you do for someone who is diagnosed?(external link)(external link) NZ Breast Cancer Foundation, 2013
Support for positive lives with secondary breast cancer(external link)(external link) Sweet Louise, NZ
Look good feel better(external link)(external link) Free Feel Better Class for any cancer patient with any cancer
More breast cancer support groups