How common is breast cancer?
Breast cancer is fairly common. One in eight Australian women will develop breast cancer before the age of 85. About 12,000 women and 84 men were diagnosed with breast cancer in 2002 in Australia. It it predicted that by 2011, the number of new diagnoses will increase to about 14,800 women and 122 men.
Breast cancer can occur at any age. The average age of women when they are diagnosed with breast cancer is 59 years. However, about a quarter of women diagnosed with breast cancer are younger than 50 years.
Breast cancer can also develop in men, although this is rare. Male breast cancer accounts for about 1% of all breast cancer.
How does breast cancer develop?
We don't know exactly how long breast cancer takes to develop, but it usually grows slowly. It can be several years before a breast cancer becomes big enough to be detected.
Breast cancer starts in the ducts or lobules of the breast. If the cancer cells spread outside the ducts or lobules of the breast into the surrounding tissue, this is called invasive breast cancer. Early breast cancer is an invasive breast cancer. Invasive cancer cells sometimes spread outside the breast area to other parts of the body. They do this by moving through blood vessels, such as veins, or through lymphatic vessels. Lymphatic vessels are next to veins in the body, and are connected to lymph nodes (glands). Lymph nodes collect normal fluid and dead cells from the lymphatic vessels.
If the cancer cells are contained in the breast and armpit area, then the cancer is 'early breast cancer'. If the cancer has spread to places near the breast, such as the chest (including the skin, muscles or bones of the chest), but the cancer isn't found in other areas of the body, this is called locally advanced breast cancer. If the cancer cells spread from the breast and are found in other areas of the body, such as the bones or the lungs, this is called metastatic breast cancer.
