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 is 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.
Breast cancer statistics in Australia
These statistics are as of October 2008.
- Breast cancer is the most common invasive cancer among Australian women
- The number of women diagnosed with breast cancer in Australia increased from 5,370 in 1983 to 12,126 in 2004
- The average age of first diagnosis was 60 years for a woman
- The risk of breast cancer increases with age
- About 24 per cent of new breast cancer cases diagnosed in 2002 were in women younger than 50 years; 50 per cent in women aged 50-69; and 26 per cent in women aged 70 and over
- Breast cancer in males is rare. The number of new cases of breast cancer in males per year increased from 43 in 1983 to 109 in 2004
- In 2002 the average age of first diagnosis was 66 years for a man
- Breast cancer is the most common cause of cancer-related death in women in Australia
- There were 2,719 female deaths in 2005
- Australia’s death rate from breast cancer was lower than the rates for New Zealand, the United Kingdom, Canada and the United States of America
- For women, there was a significant increase in relative survival after diagnosis of breast cancer between 1982-1986 and 1998-2004. Five-year relative survival increased from 71.8% to 87.8%. Five-year relative survival was 98% for women with 0-10 mm tumours, 95% for women with 11-15 mm tumours, 93% for women with 16-19 mm tumours, 88% for women with 20-29 mm tumours, 73% for women with tumours 30mm or greater
- Five-year relative survival was 97% for women with negative nodal status, 80% for women with positive nodal status
While 75% of breast cancer cases develop in women 50 years and older, younger women can still develop the disease. 5.7% of new breast cancer cases are among women under the age of 40 years.
In Australia each year, about 700 women under the age of 40 years are diagnosed with breast cancer. Overall survival from breast cancer has increased in recent years. Most recent data shows that about 90% of women aged between 40 and 69 years at diagnosis will be alive after 5 years. However, for women younger than 40 years, survival is lower. Of younger women diagnosed with breast cancer, approximately 82.4% of those aged 20-29 years and 84.8% of those aged 30-39 years will be alive 5 years after diagnosis.
|Five-year relative survival (1998-2004)
|0 to 19||85|
|20 to 29||82.4|
|30 to 39||84.8|
|40 to 49||89.7|
|50 to 59||90.2|
|60 to 69||90.6|
|70 to 79||85.3|
|80 to 89||76.4|
|90 to 99||64.2|