This information is about early breast cancer, for other types of breast cancer, visit Cancer Australia's website, or call 13 11 20. See also our genetics and breast cancer, breast reconstruction and prosthesis, breast cancer trials or breast health pages.
Women and men both have breast tissue. In women, breasts are made up of milk glands. The milk gland consists of lobules, where milk is made, and tubes called ducts that take milk to the nipples. In men, the development of the lobules is suppressed at puberty by testosterone, the male sex hormone.
Both female and male breasts contain supportive fibrous tissue and fatty tissue. Some breast tissue extends into the armpit (axilla). This is known as the axillary tail.
The armpits contain a collection of lymph nodes (also called lymph glands), which are part of the lymphatic system. The lymphatic system is part of the immune system and protects the body against disease and infection.
Breast cancer occurs when the cells lining the breast ducts or lobules grow abnormally and out of control. A tumour can form in the ducts or lobules of the breast.
Women and men can both get breast cancer, although it is rare in men. Men's symptoms are similar to women's.
When the cells that look like breast cancer are still confined to the ducts or lobules of the breast, it is called pre-invasive breast cancer. The most common type of pre-invasive breast cancer is ductal carcinoma in-situ (DCIS).
Most breast cancers are found when they are invasive. This means the cancer has spread outside the ducts or lobules of the breast into surrounding tissue. The most common types are invasive ductal cancer (IDC) and invasive lobular cancer (ILC). There are several categories of invasive breast cancer:
Early breast cancer: Cancer cells are found in the breast and may have spread to lymph nodes in the armpit.
Locally advanced breast cancer: The cancer has spread to places near the breast, such as the chest (including the skin, muscles and bones of the chest), but it isn't found in other areas of the body.
Metastatic breast cancer - Cancer cells have spread from the breast to other areas of the body, such as the bones, liver or lungs. This is also called advanced breast cancer.
You may notice a change in your breast or your doctor may find an unusual breast change during a physical examination. Signs to look for include:
Changes to your breast don't necessarily mean you have breast cancer. However, if you have any symptoms, have them checked by your doctor without delay.
Some women have no symptoms and the breast cancer is found on a screening mammogram.
The exact cause of breast cancer is not known, but some factors increase the risk:
Having some of these risk factors does not necessarily mean that you will develop breast cancer. Most women with breast cancer have no known risk factors, aside from getting older.
In men, breast cancer usually occurs over the age of 60. It is most common in men who have:
Each person inherits a set of genes from each parent. Sometimes there is a fault in one copy of a gene, which stops that gene working properly. This fault is called a mutation.
About one in 20 cases of breast cancer may be caused by an inherited gene fault. The two most common breast cancer genes are called BRCA1 and BRCA2.
Women in families with an inherited gene change are at an increased risk of breast and ovarian cancer. Men in these families may also be at an increased risk of breast and prostate cancer.
People with a strong family history of breast cancer can be tested to see if they have inherited a gene change. If you would like to know more about genetic testing, talk to your doctor or breast care nurse, or call Cancer Council Helpline 13 11 20.
Breast cancer is the most common cancer in Australian women. About 13,000 women are diagnosed each year. One in nine women will be diagnosed with breast cancer by the age of 85.
Breast cancer is rare 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.
The web can be a useful source of information. The following sites are reliable sources:
Information reviewed by: Professor John Boyages, Executive Director, Westmead Breast Cancer Institute, Westmead Hospital and author, Breast Cancer: Taking Control; Lynn Buglar, Breast Physician, BreastScreen NSW; Bronwyn Chalmers, Cancer Information Consultant, Helpline, Cancer Council NSW; Susan Munro, McGrath Breast Care Nurse, Community Health/Wagga Wagga Base Hospital, Wagga Wagga; and Kathryn Rutkowski, Consumer.