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Breast cancer

Cancer is a group of several hundred diseases in which abnormal cells are not destroyed naturally by the body but instead multiply and spread out of control. Cancers are distinguished from each other by the specific type of cell involved and the place in the body in which the disease began.

Breast cancer most commonly originates in the ducts of the breast (which carry milk from the lobules to the nipple) but can also originate in the lobules (small lobes of the breast that produce milk). More rarely, breast cancer can originate in the connective tissue of the breast.

Worldwide, breast cancer is the most common cancer affecting women, representing one in four of all cancers in women. The incidence of breast cancer differs worldwide, with this disease being far more common in more developed countries compared with developing countries (although as less developed countries become more developed, a shift towards the lifestyles of developed countries brings an increase in cancers that have reproductive, dietary, and hormonal risk factors, of which breast cancer is one) (UICC 2014).

In Australia breast cancer is the most commonly diagnosed cancer in Australian women (excluding basal and squamous cell carcinoma of the skin), comprising 27% of all female cancers, and with an incidence rate of around 115 new cases per 100,000 women; it is second only to lung cancer in cancer deaths in Australian women (AIHW 2014).

graphic showing 5 in 10 women (aged 20-69) had a mammogram in the last 2 years.

More than 5 in 10

women (54%) aged 50–69 had a mammogram through BreastScreen Australia in the last 2 years.

BreastScreen Australia

In Australia, population-based breast cancer screening is available through BreastScreen Australia, which targets women aged 50–74 for two-yearly screening mammograms (women aged 40–49 and 75 years and over are also eligible).

BreastScreen Australia aims to reduce morbidity and mortality from breast cancer by using screening mammograms to detect unsuspected breast cancers in women with no symptoms, thus enabling intervention when the cancer is at an early stage. Finding breast cancer early often means that the cancer is small, which is associated with increased treatment options (NBOCC 2009) and improved survival (AIHW & NBCC 2007).

Screening mammograms work well in older women as breasts become less dense as women get older, particularly after menopause, which is why mammograms become more effective as women get closer to age 50. Incidence of breast cancer is also very high in this age group.

Mammographic screening is not recommended for women younger than 40. This is because breast tissue in premenopausal women tends to be dense, which can make it difficult to correctly identify the presence of breast cancer with mammography. The reduced accuracy of mammography in younger women produces a high risk of false positive and false negative results, which would result in a high number of unnecessary investigations and missed breast cancers. These 'harms' would far outweigh the breast cancers that would able to be detected in younger women, for whom breast cancer is relatively rare.

However, even though screening mammography is not recommended for women under the age of 40, young women can still develop breast cancer. Therefore it is important for women of all ages to be aware of how their breasts normally look and feel and promptly report any new or unusual changes to their general practitioner. For more information on BreastScreen Australia, and for the latest breast cancer screening data, see the latest Breast cancer screening in Australia report.

Further information

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For more information on BreastScreen Australia please visit www.cancerscreening.gov.au.


AIHW 2014. Cancer in Australia: an overview 2014. Cancer series no. 90. Cat. no. CAN 88. Canberra: AIHW.

AIHW & NBCC (National Breast Cancer Centre) 2007. Breast cancer survival by size and nodal status. Cancer series no. 39. Cat. no. CAN 34. Canberra: AIHW.

NBOCC (National Breast and Ovarian Cancer Centre) 2009. National Breast and Ovarian Cancer Centre and Royal Australasian College of Surgeons National Breast Cancer audit. Public Health Monitoring Series 2007 data. Sydney: NBOCC.

UICC 2014. IARC Release the Latest World Cancer Statistics. Viewed 11 May 2015.