Notes on the data: Screening programs - Breast screening

Breast screening outcomes - cancer, females aged 50 to 74 years, 2018 and 2019, and 2019 and 2020

Policy context: The data presented here are for women screened for breast cancer as a result of screening programs [1].

Breast cancer is a major health issue for Australian women. Currently, few scientifically proven strategies are available for preventing the development of breast cancer. However, research has shown that screening mammography is currently the most effective tool for the early detection of breast cancer in asymptomatic women in the target age group of women aged 50 to 69 years; and, that having a screening mammogram every two years, reduces the chance of dying from breast cancer by up to 40%. Participation in breast screening in South Australia is associated with a reduction in breast cancer mortality of between 30% and 41% [2].

BreastScreen Australia is the national breast cancer screening program with services provided by state and territory-based organisations. The program provides screening and assessment services on a state-wide basis at no cost to eligible women, using fixed and mobile clinics. The target age group is asymptomatic women aged 50 to 74 years; asymptomatic women aged 40 to 49 and 75 years and older are also able to attend [3]. Women who are eligible because of a strong family history of breast cancer are invited annually.

Screening mammograms are different from diagnostic mammograms, which are not provided by BreastScreen Australia. Diagnostic mammograms are for women who have breast symptoms and include views that target the symptomatic area. Screening mammograms are not suitable for women with breast symptoms.

Notes/ References

The data do not include women who undergo private screening; the impact of such services is estimated to be quite small – see: Department of Health and Ageing (DoHA). BreastScreen Australia evaluation: Medicare Benefits Schedule (MBS) Mammography Analysis Project. (Screening monograph no. 11/2009.) Canberra: Commonwealth of Australia; 2009.
Roder D, Houssami N, Farshid G, Gill G, Luke C, Downey P, Beckmann K, Iosifidis P, Grieve L, Williamson L. Population screening and intensity of screening are associated with reduced breast cancer mortality: evidence of efficacy of mammography screening in Australia. Breast Cancer Res Tr. 2008;108(3):409-16.
Australian Government Department of Health. BreastScreen Australia program: About the program [Internet]. [cited 2014 May 22, updated 2016 Mar 15]. Available from: http: http://www.cancerscreening.gov.au/internet/screening/publishing.nsf/Content/about-the-program

Notes: The breast screening outcomes for the 24 month period to the end of each calendar year are based on the actual number of women with cancer outcomes as an age-standardised rate of the actual number of women screened for the two corresponding calendar years. If a woman has attended more than once in the 24 months, they are counted once only, and the age is for the last screening episode attended in the 24-month period..

Breast cancers include invasive breast cancers only.

The indirectly age-standardised rate per 10,000 women screened is based on the standard population of Australia excluding Western Australia. All totals for Australian data are based on the sum of all other states and territories.

Impact on screening during COVID-19 pandemic: The number of screening mammograms performed through BreastScreen Australia significantly declined in March 2020 as the COVID-19 pandemic worsened and tighter restrictions were put in place that included a suspension of all BreastScreen services from 25 March 2020 (see Did fewer people screen for cancer during the COVID-19 pandemic? At https://www.aihw.gov.au/reports/cancer-screening/cancer-screening-and-covid-19-in-australia/contents/did-fewer-people-screen-for-cancer-during-the-covid-19-pandemic). As a result, data have been included for two screening periods.

Note: As addresses for BreastScreen data were not in geocoded form, counts of events for geographic areas (e.g., Population Health Areas (PHAs)) have been derived from a postcode to geographic area correspondence. The correspondence file apportions events in a postcode to a single or to multiple PHAs on the basis of the total population, and not on the specific age range applicable to those being screened, or of females. The PHA data are, therefore, estimates.

Geography: Data available by Population Health Area, Local Government Area, Primary Health Network, Quintile of socioeconomic disadvantage of area and Quintiles within PHNs, and Remoteness Area

Numerator: Number of individual women aged 50 to 74 years diagnosed with screen-detected breast cancers over a 24 month period ending 31 December 2019, or the 24 month period ending 31 December 2020. Note that data for both of these time periods are presented as some screening services were closed for periods of 2020 due to COVID-19.

Denominator: Women aged 50 to 74 years screened over a 24 month period ending 31 December 2019, or ending 31 December 2020

Detail of analysis: Indirectly age-standardised rate per 10,000 women screened

Source: Compiled by PHIDU based on data provided by the Australian Institute of Health and Welfare from BreastScreen NSW, BreastScreen Victoria, BreastScreen Queensland, BreastScreen SA, BreastScreen Tasmania, BreastScreen NT, and BreastScreen ACT.