Breast cancer

What is breast cancer?

Breast cancer, like other cancers, is a disease of the body’s cells, which can start in the Breast health. Sometimes cancer cells stay in the ducts and lobules of the breast, this is called non-invasive breast cancer. If the cancer cells spread into the surrounding tissue, this is called invasive breast cancer. The site where the cancer starts is called the primary cancer.

Breast lumps (tumours) can be non-cancerous (benign) or cancerous (malignant). Non-cancerous tumours do not spread, but cancerous tumours can invade neighbouring tissues and spread to other parts of the body. This can result in new cancer deposits called secondaries or metastases.

Types of breast cancer

There are several types of breast cancer depending on where the cancer is within the breast, or if it has spread to an area outside the breast.

  • Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer that is confined to the ducts of the breast.
  • Lobular carcinoma in situ (LCIS) is a non-invasive breast cancer that is confined to the lobules of the breast. 
  • Early breast cancer is 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. Some cancer cells may have spread outside the breast and armpit area but cannot be detected. 
  • Paget’s disease of the nipple is a rare form of invasive breast cancer that affects the nipple and the area around the nipple (the areola). 
  • Inflammatory breast cancer is a rare form of invasive breast cancer that affects the skin of the breast, causing the breast to become red and inflamed. 
  • Locally advanced breast cancer is an invasive breast cancer that has spread to areas near the breast, such as the chest wall.
  • Secondary breast cancer (also called metastatic or advanced breast cancer) is an invasive breast cancer that has spread from the breast to other parts of the body.

How is breast cancer diagnosed?

Breast cancer is sometimes found after symptoms appear, but many women with early breast cancer have no symptoms. This is why getting the recommended What is a breast screen? before any symptoms develop is important.

Diagnosis of breast cancer involves the triple test. This includes:

  • a clinical breast examination
  • imaging tests – which may include a mammogram or ultrasound
  • taking a sample of tissue (biopsy) from the breast for examination under a microscope.

Other tests, such as blood tests or bone scans, may be done if symptoms suggest that breast cancer has spread outside the breast. Magnetic resonance imaging (MRI) may be suggested to assess extent of disease in some cases.

What are the symptoms of breast cancer?

Breast changes that may indicate breast cancer include:

  • a new lump or lumpiness, especially if it's only in one breast
  • a change in the size or shape of the breast
  • a change to the nipple, such as crusting, ulcer, redness or inversion
  • a nipple discharge that occurs without squeezing
  • a change in the skin of the breast such as redness or dimpling
  • an unusual pain that doesn't go away.

There are a number of conditions that may cause these symptoms, not just breast cancer. If any of these symptoms are experienced, it is important that they are discussed with a doctor.

What are the risk factors for breast cancer?

A risk factor is any factor that is associated with an increased chance of developing a particular health condition, such as breast cancer. There are different types of risk factors, some of which can be modified and some which cannot.

It should be noted that having one or more risk factors does not mean a person will develop breast cancer. Many people have at least one risk factor but will never develop breast cancer, while others with breast cancer may have had no known risk factors. Even if a person with breast cancer has a risk factor, it is usually hard to know how much that risk factor contributed to the development of their disease.

  • being a woman
  • increasing age
  • having a strong family history of breast cancer
  • having a breast condition such as a personal history of breast cancer, DCIS or LCIS
  • a number of hormonal factors, child-bearing history, personal and lifestyle factors
  • obesity (poor diet and inadequate exercise) and
  • excess alcohol consumption.


Staging involves assessing the size of the breast cancer and whether it has spread to the draining lymph nodes under the arm. A CT scan of the chest and liver and bone scan are done to check the sites to which breast cancers most commonly spread.

Treatment options

Treatment and care of people with cancer is usually provided by a team of health professionals – called a multidisciplinary team.

Treatment for breast cancer depends on the stage and type of the disease, the severity of symptoms and the person’s general health. Treatment usually involves surgery to remove part or all of the affected breast, and removal of one or more lymph nodes from the armpit. Breast reconstruction may be available for women who have the whole breast removed (mastectomy). Radiotherapy, chemotherapy, hormonal therapies, and/or targeted therapies, may also be used.

Finding support

People often feel overwhelmed, scared, anxious and upset after a diagnosis of cancer. These are all normal feelings.

Having practical and emotional support during and after diagnosis and treatment for cancer is very important. Support may be available from family and friends, health professionals or special support services.

The facts - Did you know?

  • In 2008, the risk of developing breast cancer before the age of 85 was 1 in 8
  • More than half of all breast cancers in Australia are discovered by the woman herself or her own doctor
  • Early detection saves lives – the earlier a cancer is discovered, the greater the chances of successful treatment
  • Nine out of 10 breast changes are not due to cancer, but you should see your doctor to be sure
  • Breast cancer is the most common cancer in Australian women. About 13,000 women are diagnosed each year.
  • Breast cancer is also diagnosed in men. About 100 men are diagnosed in Australia each year. This represents less than 1% of all breast cancers
  • Although it can occur at any age, breast cancer is more common in older women. The average age at diagnosis is 60. About one-quarter of women who are diagnosed are younger than 50 years of age

For more information on breast cancer, see Cancer Australia or Cancer Council South Australia

Sections of the content of this web page are reproduced with permission from Cancer Australia.