Breast Cancer

Breast cancer develops when cells grow irregularly in the breasts and become cancerous tumours.

Last modified: November 1, 2021

Quick facts about breast cancer Quick facts

  • In 2022, it is estimated that almost 20,700 Australians will be diagnosed with breast cancer. 99% of these cases are women
  • It’s predicted that in 2022, breast cancer will be the second most commonly diagnosed type of cancer in Australia
  • Here’s some good news: Australia has one of the best survival rates for breast cancer in the world, with a five -year survival rate of 92%

Types of breast cancerTypes of breast cancer

There are many different types of breast cancer, some of which are common, while others are very rare. Some of these include:

IDC is the most common type of breast cancer. Invasive means that the cancer has begun to invade breast tissue close to where it originated. In the case of IDC, the cancer began in the milk duct and has now spread through the duct wall to other breast tissue.

Rather than beginning in the milk duct, ILC originates in the milk glands (known as lobules) and invades nearby areas of the breast.

Unlike other types of breast cancer, IBC does not involve a lump in the breast. Instead, the skin of the breast may become red, inflamed, thick or pitted (like an orange), your nipple may become inverted, and the breast may become swollen, hard, tender and painful, or itchy. IBC is a rare type of breast cancer and is more likely to be advanced upon diagnosis, as it is difficult to identify using a mammogram.




Signs and symptoms of breast cancerSigns and symptoms

Breast tissue can typically feel lumpy, which can make it difficult to know what is normal and what could be a sign of breast cancer. This is why it’s important to perform regular self-examinations and see your GP or healthcare professional if you notice any of the symptoms below. Discussing anything concerning with your doctor as soon as possible can help give you peace of mind and offer the best chance of successful treatment if you receive a breast cancer diagnosis.

Some common symptoms to look out for include:

  • Changes in the size or shape of your breast

  • Any new lumps in the breast or under your arm

  • Discharge or fluid (other than breast milk) from the nipple, including blood

  • Dimpling or a ‘pulling’ of the skin on your breast

  • Breast pain or swelling

  • Dry, flaky red skin around the nipple area

Stages of breast cancerStages

The TNM system is used to stage breast cancer, and it helps doctors understand what your cancer looks like. The TNM stands for:

  • Tumour – the depth of invasion through bladder wall
  • Node – is a measure of whether lymph nodes have been affected
  • Metastasis – the degree to which the cancer has spread to other organs of the body

The TNM information, along with other tests, helps determine the stage of your breast cancer using the guidelines below.

Stage I

Cancer in breast tissue. Tumour is less than 2cm across in size

Stage II

Cancer in breast tissue. Tumour is less than 5cm in size. Cancer may spread to the axillary lymph nodes

Stage III

Tumour is larger than 5cm across in size and cancer has spread to axillary lymph nodes. Possible dimpling, inflammation or skin colour change

Stage IV

Cancer has spread beyond the breast to other nearby areas of the body

Following a breast cancer diagnosis, further testing is then done to identify the receptor status of the cancer.

Learn more about how breast cancer is classified based on receptor status.

Treatment for breast cancer

There are many different types of treatment for breast cancer. Your treatment will depend on you and your cancer.


Frequently asked questions about breast cancerFAQs

Is breast cancer hereditary?

Breast cancer is rarely hereditary. In 5-10% of cases, breast cancer is caused by specific gene mutations in the BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two) genes. However, there are several other genes that help make up this percentage.

Learn more about the role of BRCA1 and BRCA2 in developing breast and ovarian cancer.

What causes breast cancer?

There’s no one cause of breast cancer, however genetic, lifestyle and environmental factors can all increase your risk. Risk factors include:

  • Being female
  • Having a family history of, or close relative who has had breast cancer.
  • Ageing – women who are aged 50 years have a 10 times increased risk of breast cancer compared to women who are 30 years.11
  • Drinking alcohol – there is an increased risk of breast cancer with each additional unit of alcohol consumed. 11
  • Being overweight
How common is breast cancer in men?

Breast cancer in men is not that common, and only makes up 1% of all breast cancer cases (give or take). Like women, there are a number of factors that can increase the risk for breast cancer for men, including:

  • Age – the average age of breast cancer diagnosis is 69 years.
  • Hormonal imbalances – such as increased levels of oestrogens
  • Family history of breast cancer, or a known BRCA gene mutation
  • Previous radiotherapy treatment

For more information, you can look at the Breast Cancer Network Australia’s booklet – ‘Men get breast cancer too’

What can I do to decrease my risk of developing breast cancer?

There are several lifestyle factors you can control to help reduce your risk of developing breast cancer, including:

  • Getting regular exercise – Cancer Australia recommends at least 30 minutes of moderate-intensity exercise each day.
  • Eating a healthy, balanced diet – Eat a fibre-rich diet from grain and legume sources, as well as enjoy a variety of fruit (2 serves) and vegetables (5 serves) per day, limit your intake of salt, saturated fats, and avoid all processed meat.
  • Reducing your alcohol intake – If you choose to drink, try to limit your alcohol intake to no more than two standard drinks a day.
  • Maintaining a healthy weight – Cancer Australia recommends maintaining a healthy weight, within the normal BMI (Body Mass Index) range of 18.5 – 24.9kg/m2.14. To calculate your BMI = (weight (kg))/(height(m))2
How do you perform a breast self-examination?

Becoming familiar with your breasts and how they look and feel through monthly breast self-examinations can help you identify any changes at an early stage. This is particularly important for women aged below 40 who are not yet eligible for breast screening.

Read advice on performing a breast self-examination and the importance of being breast aware.

Does hormone replacement therapy (HRT) increase the risk of breast cancer?

There’s convincing evidence that combined (oestrogen-progesterone) replacement therapy increases the risk of breast cancer. Risk increases with the duration of HRT use and is higher in women who start replacement therapy close to menopause.

Are there clinical trials available for breast cancer that I can participate in?

Icon delivers Australia’s largest private cancer clinical trials and research program participating in international and national trials across medical oncology, haematology and radiation oncology. If you would like more information on participating in a clinical trial, please speak with your doctor.

See current clinical trials delivered by Icon Cancer Centre.


For a full list of references, click here.
  1. Australian Government. (2022). Cancer Australia, Cancer types. Retrieved on 20th February 2022 from
  2. (n.d). Genetics. Retrieved on 18th December 2018 from
  3. National Breast Cancer Foundation. (n.d). Stages, types and treatment of breast cancer. Retrieved on 18th December 2018 from
  4. American Cancer Society. (2017). Breast Cancer Stages. Retrieved on 19th December 2018 from
  5. Centre for Disease Control and Prevention (CDC). (2018). What are the symptoms of breast cancer. Retrieved on 18th December 2018 from
  6. National Breast Cancer Foundation. (n.d). Breast Self-Exam. Retrieved on 18th December 2018 from
  7. Cancer Australia. (2018). Risk factors for breast cancer: A review of the Evidence. Retrieved on 18th December 2018 from
  8. Cancer Australia. (n.d). Australian Government. Physical Activity and sedentary behaviour. Retrieved on 18th December 2018 from
  9. Cancer Australia, Australian Government. (n.d). Diet. Retrieved on 18th December 2018 from
  10. Cancer Australia, Australian Government. (n.d). Overweight and obesity. Retrieved on 18th December 2018 from
  11. National Breast Cancer Foundation. (n.d). Stage 0 – pre-breast cancer. Retrieved on 13th January 2019 from
  12. National Breast Cancer Foundation. (n.d). Stage 1 or 2 – Early breast cancer. Retrieved on 13th January 2019 from
  13. National Breast Cancer Foundation. (n.d). Stage 2 or 3 – Locally advanced breast cancer. Retrieved on 13th January 2019 from
  14. National Breast Cancer Foundation. (n.d). Stage 4 – Metastatic breast cancer. Retrieved on 13th January 2019 from
  15. Breast Cancer Network Australia (BCNA). (2016). Men get breast cancer too. Retrieved on 14th January 2019 from
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