Skip to Content Skip to Navigation

What is Breast Cancer?

Breast cancer occurs when cells in the breast start to change and grow abnormally and in an uncontrolled way. A gradual build up of these cells can form a lump, which is known as a tumour or a mass.

Marina Kochetkova, Breast cancer researcher

Lumps in the breast can be benign (non-cancerous) or malignant (cancerous).

Unfortunately, if left untreated, the primary tumour can spread via the lymph nodes or blood vessels to other parts of the body including the liver, lungs and bones. The spread of cancer can create more tumours around the body, which is called metastasis.

Breast cancer affects both women and men, but is the most common cancer affecting Australian women. In 2021, breast cancer was the most commonly diagnosed cancer in Australia.

A/Prof Phil Gregory

Types of Breast Cancer

Some breast cancers, known as ‘pre-invasive’ or ‘carcinoma in situ’ breast cancers, appear inside the milk ducts or milk-producing lobules of the breast. Other ‘invasive’ breast cancers grow within normal breast tissue and may spread to elsewhere in the body. There are various types of breast cancer, including

  • Paget’s disease
  • Inflammatory breast cancer
  • Ductal carcinoma
  • Lobular carcinoma
  • Hormone receptor positive breast cancer
  • HER-2 positive breast cancer
  • Triple negative breast cancer (which tests negative for oestrogen, progesterone and HER-2).
Lee Anne terminal, triple negative breast cancer

Stages of Breast Cancer

Breast cancer is most commonly divided into stages based on the tumour size and how much it has spread around the body. Breast cancer has five main stages, from 0 to 5 and this is determined based on a number of factors including:

  • Size of the tumour
  • If the cancer is invasive or non invasive
  • If the cancer has spread to nearby tissue or organs
  • If lymph nodes have been affected.
Michelle Bradley with kids   breast cancer   THRF Tax Appeal

Male Breast Cancer

Although not as common, 1 in 700 Australian men will be diagnosed with breast cancer each year and is just as serious as the breast cancer females are diagnosed with.
Males do develop the same symptoms as females. It is strongly encouraged for anyone experiencing symptoms to get checked by their local doctor.

Donate