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Breast cancer is cancer that forms in the cells of the breasts. Symptoms may include a lump in the breast, discharge from the nipple or changes in the appearance of the breast or nipple.

Learn more about breast cancer, including the risk factors, breast self-checks and cancer screening.

Topics on this page

What is breast cancer?

Breast cancer is an abnormal growth of cells in the breast. There are different types of breast cancer, but they all start in the milk ducts or milk-producing glands. The cancer may grow into surrounding tissue and spread to other organs in the body.

Breast cancer is the most common type of cancer in women in Australia. About one woman in every eight is diagnosed with breast cancer before the age of 85. But many more women in Australia die of heart disease and stroke compared with breast cancer.

Breast cancer risk factors

You can’t change many of the risk factors for breast cancer. For example:

  • being female
  • getting older – about 75% of breast cancer cases occur in women aged 50 and over
  • having a strong family history of breast cancer
  • having a faulty gene.

It’s important to note that having risk factors doesn’t mean you will get breast cancer.

Around 90% to 95% of breast cancers have nothing to do with family history. The other 5% to 10% occur in people who have inherited a faulty gene.

There are other risk factors associated with breast cancer. For example:

  • having dense breasts
  • being overweight
  • drinking alcohol
  • smoking
  • having radiation to your face or chest before age 30
  • having a previous history of breast cancer.

Trans women who take medicine to lower male hormones and increase female hormones may be at increased risk of breast cancer compared to cis men.

You can read more about the risk factors by visiting the following websites:

You can also learn about your individual risk by using the risk calculator on the iPrevent page of the Peter Mac website. If you are concerned about your risk of breast cancer, talk to your doctor.

Breast self-checks and cancer screening

Breast self-checks

It’s important to be ‘breast aware’. Know how your breasts look and feel so you can act quickly if you notice any changes.

Look at and feel your breasts regularly. You can do this in the shower, when you use body lotion, or in front of the mirror. Check all parts of your breasts including your armpits and the area up to your collarbone.

As breasts can feel different before and after your period, it’s a good idea to know what’s normal during these times. Knowing your breasts makes it easier to notice changes.

Changes you should look for include:

  • new lumps in your breast or armpit
  • thickening or swelling
  • changes in the shape of your breast
  • changes in the size of your breast
  • changes in the colour of your breast.

You should also look for:

  • changes in your nipples
  • discharge from your nipple
  • puckering or dimpling of breast skin
  • persistent breast pain
  • persistent nipple or breast itching or rash.

If you notice anything that’s not normal for you, see your doctor as soon as possible. Most changes are not related to cancer, but it’s important to make sure. The earlier breast cancer is diagnosed, the better the outcome.

Learn how to do breast self-checks.

Breast cancer screening

Breast cancer screening is a safe X-ray of your breasts that can sometimes show cancer before there are any signs or symptoms. Breast screening is also called a ‘mammogram’.

Breast screening aims to find cancer while it’s still small and confined to the breast. Early detection gives you the best chance of effective treatment.

Learn more about breast cancer screening.

This con­tent has been reviewed by a group of med­ical sub­ject mat­ter experts, in accor­dance with Jean Hailes pol­i­cy.

Australian Institute of Health and Welfare, Cancer in Australia 2021
Cancer Australia, Breast Cancer Statistics
Breast Cancer Network Australia, Risk factors
Breast Cancer Network Australia, Understanding genetic testing
Last updated: 
26 April 2024
Last reviewed: 
15 November 2023

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