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  • What is breast cancer?


    The Breasts

    Women and men both have breast tissue.

    In women, breasts are made up of milk glands. A milk gland consists of:

    • lobules – where milk is made
    • ducts – tubes that carry 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 and fatty tissue. Some breast tissue extends into the armpit (axilla). This is known as the axillary tail.

    Lymphatic system

    The lymphatic system is part of the immune system and protects the body against disease and infection. It is made up of a network of thin tubes called lymph vessels. These connect to groups of small, bean-shaped structures called lymph nodes or glands.

    Lymph nodes are found throughout the body, including the armpits (axillary), the breastbone, the neck, abdomen and groin. 

    Breast cancer

    Breast cancer occurs when the cells lining the breast lobules or ducts grow abnormally and out of control. A tumour can form in the lobules or ducts of the breast.

    Women and men can both get breast cancer, although it is rare in men. About 130 men are diagnosed in Australia each year. This represents less than 1% of all breast cancers. Men’s symptoms are similar to women’s. Click here for more information on breast cancer in men.

    Breast cancer is the most common cancer in Australian women, representing 28% of all cancers in women. About 14,000 women are diagnosed each year. One in eight women will be diagnosed with breast cancer by the age of 85.

    Although it can occur at any age, breast cancer is more common in older women. More than two in three (69%) are diagnosed in women aged 40–69. About one in four (25%) are diagnosed in women aged 70 and over.

    Nearly 80% of women diagnosed had Invasive Ductal Carcinoma, while about 11% had Invasive Lobular Carcinoma. 

    Types of breast cancer

    There are several types of breast cancer.

    Non-invasive breast cancer

    Ductal carcinoma in situ (DCIS) – Abnormal cells are contained within the ducts of the breast. 

    Invasive breast cancer

    Early breast cancer – This means the cancer has spread from the ducts or lobules into surrounding breast tissue. It may also have spread to lymph nodes in the armpit. Most breast cancers are found when they are invasive. The most common types are invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC).

    Locally advanced breast cancer – The cancer has spread to other areas near the breast, such as the chest (including the skin, muscles and bones of the chest). 

    Secondary breast cancer

    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.

    Lobular carcinoma in situ (LCIS)

    Some women have abnormal cells in the lobules of the breast. This is called lobular carcinoma in situ or LCIS. This is not cancer. While LCIS increases the risk of developing cancer, most women with this condition will not develop breast cancer. Your medical team will monitor you with regular mammograms or other types of breast imaging.

    Symptoms of 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:

    • A lump, lumpiness or thickening.
    • Changes to the nipple such as a change in shape, crusting, a sore or an ulcer, redness, unusual discharge or a nipple that turns in (inverted) when it used to stick out.
    • Changes to the skin of the breast, such as dimpling of the skin, unusual redness or other colour changes.
    • An increase or decrease in the size of the breast.
    • A change to the shape of the breast.
    • Swelling or discomfort in the armpit.
    • Persistent, unusual pain that is not related to your normal monthly menstrual cycle, remains after a period and occurs in one breast only.

    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. Women aged 50–74 should have regular screening mammograms through BreastScreen. Call 13 20 50 to make an appointment for a free mammogram.

    Risk factors

    The exact cause of breast cancer is not known but some factors increase the risk:

    • getting older (most common in women over 50)
    • having several close relatives, such as a mother, father, sister or daughter, diagnosed with breast cancer on the same side of the family
    • if you have had breast cancer before
    • if you have certain breast conditions, such as atypical ductal hyperplasia, ductal carcinoma in situ or lobular carcinoma in situ

    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.

    Inherited breast cancer gene

    Most women diagnosed with breast cancer do not have a family history of the disease. However, a small number of women with breast cancer (about one in 20) have inherited a gene fault that increases their risk. The two most common breast cancer genes are called BRCA1 and BRCA2.

    Everyone inherits a set of genes from each parent, so they have two copies of each gene. Sometimes there is a fault in one copy of a gene, which stops that gene working properly. This fault is called a mutation.

    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 13 11 20

    This website page was last reviewed and updated February 2016.

    Information last reviewed August 2014 by: Dr Carolyn Cho, Breast and General Surgeon, Surgical Oncology, Deakin, ACT; Lynn Buglar, Breast Physician, BreastScreen, NSW; Mena Crew, Consumer; Elizabeth Jacobson, Consumer; Jane Marsh, Clinical Manager, Breast Centre, Brian Fricker Oncology Centre and Burnside War Memorial Hospital, SA; Marie Murdoch, Breast Care Nurse, Cancer Council Queensland, QLD; and Marion Strong, Clinical Nurse Consultant Breast Care Nurse and Cancer Care Coordinator, Toowoomba Hospital, QLD

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