Learn more about breast cancer types, symptoms, risk factors and survival rates.

What is Breast Cancer?

Breast cancer is the most common cancer in women in Australia and New Zealand, and the most commonly diagnosed cancer globally.

Breast cancer occurs when abnormal or damaged cells grow in an uncontrolled manner and a tumour is formed. Most tumours start in the milk ducts which carry milk to the nipple. Both men and women can develop breast cancer although it is less common in men.

Types of Breast Cancer

Breast cancer is not just one disease, but several. It includes different subtypes and treatments are becoming increasingly personalised for patients.

Non-invasive breast cancers (carcinoma in situ) are contained within the milk ducts or lobules in the breast and have not grown into the normal breast tissue:

  • Ductal carcinoma in situ (DCIS) – a non-invasive breast cancer that is confined to the milk ducts of the breast.
  • Lobular carcinoma in situ (LCIS) – a non-invasive breast cancer that is confined to the lobules or milk producing glands at the end of the milk ducts of the breast.

Invasive breast cancers are cancers that are growing in the normal breast tissue and have the potential to spread to other sites in the body:

  • Early breast cancer – an invasive breast cancer that is contained in the breast and may or may not have spread to lymph nodes in the breast or armpit.
  • Paget’s disease of the nipple – a rare form of breast cancer that affects the nipple and the area around the nipple (the areola). Commonly associated with an invasive cancer elsewhere in the breast.
  • Inflammatory breast cancer – a rare form of invasive breast cancer that affects the lymphatic vessels in the skin of the breast. This type of breast cancer does not present as a lump but rather a redness or rash in appearance.
  • Locally advanced breast cancer – an invasive breast cancer that is large or has spread to areas near the breast, such as the chest wall.
  • HER2-positive breast cancer – any type of breast cancer that tests positive for a protein called human epidermal growth factor receptor 2 (HER2).
  • Triple negative breast cancer – breast cancer that tests negative for all three receptors – oestrogen, progesterone and HER2.
  • Metastatic breast cancer – also known as advanced, secondary or stage 4 breast cancer, which has spread to other parts of the body such as the bones, liver or lungs.

How Common is Breast Cancer?

On average, 57 people in Australia and nine people in New Zealand are diagnosed with breast cancer every day. The risk of being diagnosed with breast cancer in Australia by the age of 85 is one in seven for women and one in 726 for men. For New Zealand women, the risk of being diagnosed with breast cancer is 1 in 9.

In 2021, it is estimated that 20,030 new cases of breast cancer will be diagnosed in Australia (164 males and 19,866 females). In New Zealand, approximately 3,500 people will be diagnosed with breast cancer.

A woman’s risk of developing breast cancer increases with age, with the average age of first diagnosis in women being 61 years. 79% of new cases of breast cancer develop in women over the age of 50.

Given the ageing population, the number of women diagnosed with breast cancer is expected to increase each year. However the number of deaths from breast cancer is decreasing.

Only approximately 5–10% of breast cancers are associated with a strong family history or a known genetic mutation.

Breast Cancer today inAustralia and New Zealand

Breast Cancer today In Australia

In Australia, the risk of a woman being diagnosed with breast cancer by the age of 85 is

1 IN 7

.. for men 1 in 670

… and New Zealand

In New Zealand, the risk of a woman being diagnosed with breast cancer in their lifetime is

1 IN 9

Breast Cancer Survival Rates

In Australia, breast cancer accounts for 14% of all cancer deaths in women and is the second leading cause of cancer death in women after lung cancer.

In 2021, it is estimated 3,102 women and 36 men will die from breast cancer in Australia. That’s an average of eight people every day.  This year, there will be approximately 600 deaths from breast cancer in New Zealand.

In Australia, breast cancer is the leading cause of death from cancer in women aged 20-59 years of age.  It is estimated that breast cancer will be the most commonly diagnosed cancer in Australia in 2021.

Breast cancer mortality rates have fallen by approximately 30% in the last 20 years and breast cancer clinical trials have played a large part in this improvement.

Between 1984–1988 and 2009–2013, the five-year relative survival rates from breast cancer have improved from 72% to 90% in Australia.

The chance of surviving at least five years (five-year relative survival) in Australia is 91%. In New Zealand it is 88%.

The chance of surviving at least ten years (ten-year relative survival) in Australia is 83%. In New Zealand it is 80%- 95% if detected early via a mammogram.

Breast Cancer Risk Factors

A risk factor is something about a person, or what that person is exposed to, that increases their ‘risk’ (in other words, the chance or likelihood) of developing breast cancer in future. This might be something about their genetic makeup that cannot be changed, or a lifestyle factor like alcohol of lack of exercise. But risk factors don’t tell us everything. Having a risk factor, or even several risk factors, does not mean a woman will definitely be diagnosed with breast cancer and many who are diagnosed do not have any known risk factors.

There is currently no way to definitively prevent breast cancer. However, you can assess your risk factors and their impact on your cancer risk using the iPrevent tool. Some risk factors can be modified, others cannot, and these may include:

  • Age

    The risk of breast cancer increases with age, with about 79% of all new breast cancer diagnosed in women aged 50 and over. The average age of first breast cancer diagnosis in Australia is 61 years.

    Besides gender, aging is the most significant risk factor associated with breast cancer [4]. The older you get, the more your cells accumulate DNA damage (mutations) and are therefore more likely to progress to cancer. According to Cancer Australia, women who are 50 years old are approximately 10 times more likely to develop breast cancer compared to women who are 30 years old.

  • Alcohol

    Alcohol consumption is associated with an approximate 30-50% increased risk in breast cancer risk [1]. Alcohol consumption is the most-established dietary risk factor of breast cancer thought to be due to the increase of endogenous oestrogen levels it causes [2]. 

    Your relative risk of breast cancer is increased by 7% of each additional 10 grams, or one standard drink, of alcohol consumed per day [3]. One standard drink is equivalent to 100mL of wine, 285mL full strength beer, 425mL low strength beer or 30mL (one nip) of spirits.

    Evidence shows there is no safe level of alcohol consumption in regard to breast cancer risk. A large meta-analysis of 222 articles finding even light drinking (up to one drink per day) increases the risk of breast cancer in women. The risk increases further with each extra drink.

  • Family History

    A family history of breast cancer means having one or more blood relatives who have received a breast cancer diagnosis.

    Studies have found that women with one first-degree relative with breast cancer have almost two times the risk of developing breast cancer compared to a woman without any affected relatives. Furthermore, this becomes a three times higher risk for women with two or more first-degree relatives with breast cancer [5]

    Approximately 5-10% of breast cancers are due to a strong family history (two or more close relatives) of genetic mutation such as BRCA1 or BRCA2. There are also lesser known gene-mutations linked to a higher breast cancer risk such as TP53, PTEN, CDH1 and STK11 and some rare moderate-risk gene mutations such as PALB2, ATM and CHEK2. Some women with strong family histories receive genetic testing to see if they have one of these mutations. You can learn more about genetic testing in this Breast Cancer Trials podcast.

    You can learn more about the genetic risks for developing breast cancer here.

    Breast Cancer Trials currently has a breast cancer prevention trial for those with the BRCA1 gene mutation. You can learn more here.

  • Dense Breasts

    Even though breast density is a lower risk than other risk factors such as family history, it is more common in the general population [6]. Mammographic density, or dense breasts, refers to the percentage of dense tissue of an entire breast and can be seen as the whiteness on your mammogram. Breast density cannot be felt or touched and can only be determined through x ray or mammograms.

    Women with dense breasts face two challenges; a potential late diagnosis of breast cancer due to poor sensitivity of mammographic screening and having a higher risk for developing breast cancer [7]. Researchers are uncertain as to why having dense breasts increases your breast cancer risks, but believe it has some genetic links. It is hypothesized that the greater proportion of epithelial and non-epithelial cells in areas of high breast density, and the greater cumulative exposure to hormones and growth factors, may stimulate more cell division which increases breast cancer risk [8].

    Breast density is just one risk factor and doesn’t mean you will be diagnosed with breast cancer. However, if you are aware of your mammographic density, you should talk with your doctor about regular screening. You can learn more about dense breasts in this podcast.

  • Being Overweight

    Being overweight or obese is a known breast cancer risk factor. Obesity is associated with a 20% to 40% increased risk of breast cancer in post-menopausal women. In patients diagnosed with breast cancer, obesity is associated with a 33% increased risk of cancer recurrence and of death from any cause [9].

    Additionally, gaining weight as an adult is associated with an increased risk of post-menopausal breast cancer. The risk increases by about 6% for each 5 kg increase in a woman’s weight.

    However, having a higher BMI before menopause is associated with a decreased risk of premenopausal breast cancer. For each 5-unit increase in BMI, the risk of premenopausal breast cancer is decreased by about 7% [10]. Importantly, obesity throughout life increases the risk of many other diseases such as heart disease and other cancers, leading to a higher rate of premature death.

    You should aim to lead an active life-style, with the Australian Government guidelines recommending 150 to 300 minutes (2 ½ to 5 hours) of moderate intensity physical activity or 75 to 150 minutes (1 ¼ to 2 ½ hours) of vigorous intensity physical activity, or an equivalent combination of both moderate and vigorous activities, each week if aged between 18-64. For those aged 65 and older, the recommendation is to be physically active for 30 minutes every day. This should be balanced with a healthy diet full of nutritious wholefoods [11].

  • Previous Radiation

    Previous exposure to radiation is a known breast cancer risk factor, which increased according to how much radiation you have been exposed to and when you were exposed. Age is an important factor, with females exposed before age 20 years having the highest risk and minimal risk for those exposed to radiation after menopause [12].

    Usually, this exposure to radiation therapy for young people in the chest region is due to treatment for Hodgkin lymphoma or childhood cancers. Women who were treated for hodgkin lymphoma using radiation alone have about five times the risk of breast cancer as women who did not receive this treatment. The risk is higher for those treated at a younger age, particularly close to the age when periods started [13].

  • Smoking

    Researchers have found an increased risk of breast cancer for those who smoke, particularly among women who started smoking at adolescence or younger ages. The relative risk of breast cancer associated with smoking has been found to be greater for women with a family history of the disease [14]

    The carcinogenic potential of tobacco smoke is unarguable and has been definitively linked to heart disease, lung cancer and many other cancers, therefore not smoking is the best choice for your health.

It’s important to know your personal breast cancer risk and manage any risks that can be changed, such as smoking, diet and exercise. Regular screening is important for those in the targeted age group of 50 – 74. If you are younger and concerned about your breast cancer risk, speak with your GP about your screening options.

Breast Cancer Signs and Symptoms

In the early stages of breast cancer there may be no symptoms at all. As the cancer grows, symptoms can include:

  • A new lump in the breast, armpit area or around the collarbone.
  • A change in breast size or shape.
  • Changes to the nipple, such as sores or crusting, an ulcer or inverted nipple.
  • Clear or bloody nipple discharge.
  • Changes to the skin including redness, puckering or dimpling (an ‘orange peel’ appearance).
  • Breast tenderness or pain.

breast cancer symptoms | 1

Breast Cancer Symptoms


The Australian Institute of Health and Welfare
Cancer Australia
New Zealand Breast Cancer Foundation