BreastScreen Australia is a joint program of the Australian Government and state and territory governments that aims to reduce morbidity and mortality from breast cancer. This is achieved through organised breast cancer screening to detect cases of unsuspected breast cancer in asymptomatic women, enabling intervention at an early stage. The target age group is women aged 50-69 years.
Participation and rescreening
In 2007-2008, 1,641,316 women participated in BreastScreen Australia, of whom 1,273,403 (77.6%) were aged 50-69 years. Although the number of women increased, participation of women aged 50-69 years decreased from 56.9% in 2005-2006 to 54.9% in 2007-2008.
BreastScreen Australia achieved equitable access to women across geographic regions, but participation of Aboriginal and Torres Strait Islander women remained lower at 36.0%.
The proportion of women aged 50-69 years rescreened within 27 months ranged from 59.3% after the first screen to 66.8% after the second screen and to 78.4% after subsequent screens.
Invasive cancer detection
Between 1996 and 2008, the national rate at which women are recalled to assessment to investigate mammograms suspicious for breast cancer increased from 5.8% to 9.5% of women screened for the first screening round, while for subsequent screening rounds this rate remained at around 4%. An increase in the recall to assessment rate may have contributed to the increase in the rate of detection of invasive breast cancer between 1996 and 2008. The rate increased from 56.5 to 71.7 per 10,000 women screened for the first screening round, and from 35.3 to 47.5 per 10,000 women screened for subsequent screening rounds.
Nearly two-thirds of all invasive breast cancers detected by BreastScreen Australia were small. This is an important result, since detection of breast cancers when they are small leads to more options for treatment and improved survival.
While screen-detected cancer detection rates were high, interval cancer rates were low. For the 0-12 months after a negative screening episode, these rates were 6.3 and 6.5 interval cancers per 10,000 women-years for the first and subsequent screening rounds respectively.
Incidence and mortality
Incidence and mortality rates for breast cancer for Australian women have changed between 1991, when BreastScreen Australia commenced, and the most recent year for which these data are available.
Incidence for women aged 50-69 years increased from 230.1 new cases per 100,000 women in 1991 to 287.7 in 2006, with a peak of 304.8 in 2001. Conversely, mortality from breast cancer for women aged 50-69 years has decreased steadily, from 68.2 deaths per 100,000 women in 1991 to 47.0 deaths per 100,000 women in 2007.
While Aboriginal and Torres Strait Islander women experienced lower incidence of invasive breast cancer than non-Indigenous women, mortality was found not to differ.