Technical notes

Activity data

National Bowel Cancer Screening Program

Invitations issued are a count of all screening invitations issued within the relevant period, for those within the target age group. Two-yearly screening was only fully rolled out from 2020, and prior to that specific ages invited within the 50–74 were invited to screen each year. This phasing in of age groups is also reflected in quarterly activity counts. The age groups invited for the periods covered in this report are shown in the section NBCSP age groups invited by year.

Total kits returned are a count of all kits returned during the relevant period. This can include kits issued in a previous period and returned at a later date. It can also include multiple kits per person (invitee) due to expired, spoiled, damaged, or incorrectly completed kits.

Although terminology is similar, activity counts of invites issued or screening kits returned should not be directly compared with the formal NBCSP participation indicator. Activity counts are a count of events, not people.

National Cervical Screening Program

Screening tests are a count of all primary HPV screening tests performed within the relevant period for those within the target age group. Follow-up tests for people who had a positive screening test, or treatment for HPV infection, are not included. Transition from the previous two-yearly screening program to the renewed 5-yearly screening program occurred from 1 December 2017. Quarterly activity counts are only shown for the renewed NCSP from 2018 onwards as program data for previous years are not comparable.

Although terminology is similar, activity counts of screening tests should not be directly compared with the formal NCSP participation indicator. Activity counts are a count of events, not people.

BreastScreen Australia

Activity data for BreastScreen Australia are not presented as data are not available.

Age-specific rates

The number of cases occurring in each specified age group divided by the corresponding population in the same age group. For example, in this report age-specific participation rates are calculated as the number of people participating in a screening program, divided by the number of people eligible to participate (or the number of people in the population of that age), expressed as a percentage.

Age-standardised rates

Age-standardisation is a way to remove the influence of age when comparing populations with different age structures (or relative number of people in each age group in a population). This is usually necessary because the rates of many diseases vary strongly (usually increasing) with age. The age structures of the different populations are converted to the same ‘standard’ structure, and then the disease rates that would have occurred with that structure are calculated and compared.

In this report, all rates reported (including national rates reported for a single reporting period) are age-specific (crude) rates, unless otherwise stated. Age-standardised participation rates for the target age group for BreastScreen Australia (50–69 and 50–74) and the National Cervical Screening Program (25–74) are available in the accompanying data tables, to allow comparisons to be made over time and across population groups.

Age-standardised participation rates are not available for the National Bowel Cancer Screening program, due to the fact that only specific age groups were invited until the program was fully rolled out in 2020. For more information about the age groups invited in different years, see the section in the Technical notes, ‘National Bowel Cancer Screening Program age groups invited by year’.

Data sources

This report uses data from:

  • the National Cancer Screening Register for bowel and cervical screening data
  • the National Bowel Cancer Screening Register, for participation data for reporting periods prior to 2018-2019
  • state and territory cervical screening registers, for reporting periods prior to 2018
  • state and territory BreastScreen Australia registers.

Data updates

Data in this report are sourced from live databases, which are updated over time, with later data supply likely to have a greater level of completeness. Data in this report may differ from other AIHW cancer screening reports, which are sourced at a different time.

Activity data for cervical and bowel cancer screening are updated each quarter.

Preliminary participation data for cervical, breast and bowel cancer screening are published ahead of the respective AIHW annual monitoring report for each program to give key stakeholders and policy-makers early access to these important data. As more recent data are used to update participation when the respective AIHW annual monitoring reports are released, preliminary participation data are subject to change.

Geography

Participation rates in BreastScreen Australia, the NBCSP and the NCSP are presented for the following geographies:

  • Primary Health Network (PHN) areas: 31 areas covering Australia, defined by the Department of Health (Department of Health 2018).
  • Statistical Areas Level 3 (SA3s): 333 areas covering Australia.

Participation rates in the NBCSP are also presented for Statistical Areas Level 2 (SA2s): 2,196 areas covering Australia (for periods up to 2017–2018). SA2 data for the NBCSP were not available for 2018–2019 at the time of preparation of this report.

Both SA3s and SA2 are defined by the ABS within the Australian Statistical Geography Standard (ASGS):

  • The 2011 ASGS was used for the NBCSP, and 2014–2015 and 2015–2016 BreastScreen Australia data in this report.
  • The 2016 ASGS was used for the NCSP and 2016–2017 and later BreastScreen Australia data in this report.

For BreastScreen Australia and the NCSP, population denominators for the PHN geographical areas were derived using ABS Estimated Resident Population (ERP) data by postal areas (ABS 2020) and the PHN correspondence file. These data were classified according to the PHN 2017 structure (ABS 2016).

Participation data for some SA3s across the three screening programs were not published due to reliability concerns arising from low numbers in these regions and/or due to poor correspondence (as determined by the Australian Bureau of Statistics).

Assigning geography

For NBCSP invitees, geographic areas (PHN areas, SA3s and SA2s) were assigned using Statistical Area Level 1 (SA1) of usual residence. For invitees without reliable SA1 details geographic areas were assigned using postcode of usual residence. As some postcodes cross the boundaries of PHNs, SA3s or SA2s the use of postcode correspondences may lead to some minor inaccuracies in results. For the 2018-2019 reporting period, participation by PHN and SA3 geographical areas were reported and assigned using postcode of usual residence.

Where SA1 codes and postcodes could not be attributed to a PHN, SA3 or SA2, these invitees were included in an 'Unknown' group in the data tables, and are excluded from data visualisations.

For BreastScreen Australia and the NCSP, PHN areas and SA3s were assigned using postcode of usual residence. Where postcodes could not be attributed to a PHN or SA3, these women were included in an 'Unknown' group, where possible in the data tables, and were excluded from data visualisations. For analyses where a postcode or SA1 boundary overlapped PHN areas, SA3 or SA2 boundaries, the relevant records were attributed based on the percentage of the population within that postcode or SA1 that fell within the PHN area SA3, or SA2.

Participation by geographic areas represents the geographic data available within the relevant data source at the time of first publication, and are not retrospectively updated. This is particularly of relevance to NCSR data for the NBCSP as some improvements to geographical information may be made over time.

Correspondences

Correspondence files for PHN were sourced from the Australian Statistical Geography Standard (ASGS): Volume 3 - Non ABS Structures (ABS 2010b, 2016b). For the NBCSP and BreastScreen Australia data for 2014–2015 and 2015–2016, data were classified according to the PHN 2015 structure (ABS 2011). BreastScreen Australia 2016–2017 and later data were classified according to the PHN 2017 structure (ABS 2016). PHNs were established in June 2015, and some of the geographic information presented includes data before that date. For further details on PHNs see the Department of Health’s website.

For the NBCSP and BreastScreen Australia data for 2014–2015 and 2015–2016, correspondence files for SA3s and SA2s were sourced from Australian Statistical Geography Standard (ASGS) 2011: Volume 1 (ABS 2010a). For 2016–2017 onwards BreastScreen Australia data correspondence files for SA3s were sourced from Australian Statistical Geography Standard (ASGS) 2016: Volume 1 (ABS 2016a).

The correspondences produced by the ABS can be found on data.gov.au by searching for: ‘ASGS’, the 'year', and ‘correspondences’.

The number of people in different geographic areas (PHNs, SA3s or SA2s) may not sum to 'Australia' total due to rounding. The Australia total also includes some records that could not be attributed to a geographic area.

SA3s and SA2s with a numerator less than 20 or a denominator less than 100 were suppressed.

For a full list of AIHW products that include data and results by small areas (for example, by Primary Health Network areas) see AIHW data by geography.

National Bowel Cancer Screening Program age groups invited by year

Two-yearly screening was only fully rolled out from 2020. The specific ages invited within the 50–74 age for the periods covered in this report are shown in the following table:

National Bowel Cancer Screening Program ages invited by year
Phase Start date End date Ages invited

1

7 August 2006

30 June 2008

55 and 65

2

1 July 2008

30 June 2011(a)

50, 55 and 65

2(b)

1 July 2011

30 June 2013

50, 55 and 65

3

1 July 2013

Ongoing

50, 55, 60 and 65

4

1 January 2015

31 December 2015

50, 55, 60, 65, 70 and 74

4

1 January 2016

31 December 2016

50, 55, 60, 64, 65, 70, 72 and 74

4

1 January 2017

31 December 2017

50, 54, 55, 58, 60, 64, 68, 70, 72 and 74

4

1 January 2018

31 December 2018

50, 54, 58, 60, 62, 64, 66, 68, 70, 72 and 74

4

1 January 2019

31 December 2019

50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72 and 74

(a) Eligible birth dates, and thus invitations, ended on 31 December 2010.

(b) Ongoing NBCSP funding commenced.

Note: The eligible population for all Phase 2 and 3 start dates incorporate all those turning the target ages from 1 January of that year onwards.

Participation rates

National Bowel Cancer Screening Program

Participation rates represent the percentage of people invited to screen through the NBCSP during the relevant 2-year period, who returned a completed screening test within that period or by 30 June of the following year. The number of individuals invited to screen excludes those who deferred or opted out without completing their screening test. As two-yearly screening was only fully rolled out from 2020, the specific ages invited within the 50–74 age group for the periods covered in this report are shown in the section ‘National Bowel Cancer Screening Program age groups invited by year’.

BreastScreen Australia

Participation rates represent the percentage of women in the population aged 50–74 screened by BreastScreen Australia over 2 calendar years. The population denominator was the average of ABS Estimated Resident Population (ERP) for females aged 50–74 within the relevant geographical area (PHN, SA3) for the relevant 2-year reporting period.

BreastScreen Australia changed its target age group from 50–69 years to 50–74 years from July 2013; participation is reported for both the previous and current target age groups to allow comparison of trends with previously reported data.

National Cervical Screening Program

Participation in the NCSP for this report used a preliminary methodology to calculate participation until 5 years of data are available to calculate 5-year participation.  This was defined as the percentage of women in the population aged 25–74 who had at least one Cervical Screening Test in 2018 and 2019. Participation rates were calculated using the ABS Estimated Resident Population (ERP) for females aged 25–74 in 2018 and 2019, adjusted to exclude the estimated proportion of women who have had a hysterectomy and COMPASS participants. COMPASS is a clinical trial comparing 2.5-yearly Pap test screening with 5-yearly HPV screening by the VCS Foundation in collaboration with Cancer Council NSW.

In this report, cervical screening participation is defined as the number of people who had a screening HPV test (primary screening or 12-month repeat HPV tests). This is a change from previous reports in which participation was defined as the number of people who had an HPV test for any reason. This means participation is lower than, and not comparable to, previous reports.

This definition restricts participation to screening tests, which aligns with the definition of participation for Australia’s 2 other population-based cancer screening programs.

State or territory

For data on the National Cervical Screening Program (from 2018 onwards), and the National Bowel Cancer Screening Program, state or territory refers to the state or territory of residence.

For data on BreastScreen Australia, and the National Cervical Screening Program prior to 2018, state or territory reported refers to the state or territory in which screening occurred, not the state or territory of residence.