Risk factors for breast cancer

Almost all breast cancers arise from the cells lining the breast ducts (the channels in the breast that carry milk to the nipple). It mainly affects women. Men can also get breast cancer, but this is rare.

Risk factors for breast cancer include:

  • Getting older – most breast cancers occur in women over 50. Though breast cancer can occur at a younger age.
  • Ethnicity – Māori and Pasifika women are more likely to be diagnosed with more serious (advanced) breast cancers.
  • Family history – if you have close relatives who have had breast cancer or inherited changes in BRCA1 or BRCA2 genes.
  • Personal history of breast cancer – people who have had breast cancer before are more likely to get breast cancer a second time. 
  • Dense breasts (as seen on a mammogram) – this is inherited.
  • Reproductive history - starting periods before age 12 or menopause after age 55, aged over 30 at birth of first child, not breast feeding and not having a full-term pregnancy.
  • Exposure to Stilboestrol (also known as diethylstilboestrol DES) while pregnant. DES is a synthetic hormone that was given to some pregnant women in New Zealand between 1940-1960 to prevent miscarriage. Women who took DES or daughters whose mothers took DES while pregnant with them are at higher risk of breast cancer. 
  • Taking hormones- menopausal hormone therapy (MHT)/ hormone replacement therapy (HRT) or combined oral contraceptive pill.
  • Drinking alcohol – the more you drink the higher the risk but drinking even small amounts can increase your risk. 
  • Being overweight and weight gain in adulthood increases the risk of postmenopausal breast cancer
  • Not being physically active.

Having one or more of these risk factors does not mean that you will develop breast cancer. Some people who get the disease may not have any known risk factors.

 600x400 Breast Screening

Family history of breast cancer

Anyone with concerns about their risk of developing breast cancer should talk to their doctor. 

If you are at higher risk of developing breast cancer, you may be advised to have checks more often. This may start at a younger age.


Find breast cancer early

Breast screening

Women 45 to 69 years can have a free breast screen (mammogram) every two years. Breast screening is an X-ray mammogram. It is used to find breast cancer in people who don’t have any symptoms. Mammograms can save lives by finding breast cancer early when treatment has the best chance of being successful.

For more details contact BreastScreen Aotearoa on 0800 270 200 or visit https://www.timetoscreen.nz/

Breast awareness

All ages should be breast aware and know what to do to help find breast cancer early. There is no right or wrong way to check your breasts. Get to know the way your breasts normally look and feel and check them often.

Breast changes to look out for:

  • a change in size or shape of your breast
  • a new lump or lumpiness in your breast or armpit
  • thickening or dimpling of your skin
  • change in your nipple such as crusting, ulcer, redness or inverted (turned inwards)
  • nipple discharge
  • change in position of your nipple
  • pain in your breast or nipple that doesn't go away.

Many conditions can cause these symptoms, not just breast cancer. If you have any of these symptoms, talk to your doctor. Please do not ignore them.