The National Bowel Cancer Screening Program (NBCSP) started in 2006 with the aim of reducing morbidity and mortality from bowel cancer by screening the eligible target population for early detection or prevention of the disease. Eligible Australians (those aged 50–74 years) are sent a free screening kit (immunochemical faecal occult blood test or immunochemical faecal occult blood test (iFOBT)) and are invited to screen every 2 years. Indicators of program performance include the proportion of the eligible population who were invited and who returned a completed screening kit for analysis. A high participation rate is necessary for the NBCSP to achieve its major objective of reducing colorectal cancer incidence, morbidity and mortality.1
About this measure
Australia has one of the highest rates of colorectal cancer in the world, with this cancer projected to be the fourth most common recorded cancer in Australia in 2022 with an age standardized rate of 48.9 per 100,000 people (after prostate cancer, breast cancer, and melanoma of the skin).2, 3
Bowel cancer may be present for many years before a person shows symptoms, such as visible rectal bleeding, change in bowel habit, bowel obstruction or anaemia. Often, symptoms such as these are not present until the cancer has reached a relatively advanced stage. However, non-visible bleeding of the bowel may occur in the precancerous stages for some time. The relatively slow development of bowel cancer means that precancerous polyps and adenomas, and early-stage cancers, can potentially be screen-detected and effectively treated.1
An immunochemical faecal occult blood test (iFOBT) is a common method of bowel cancer screening. An iFOBT is a non-invasive test that can detect microscopic amounts of blood in a sample from a bowel motion, which may indicate a bowel abnormality, such as an adenoma or cancer. FOBT screening reduces the risk of CRC mortality.4
The two-yearly screening of the NBCSP was only fully rolled out from 2020 with phases in the preceding roll-out and target population shown below: 1
| Phase | Start date | End date | Target ages (years) |
|---|---|---|---|
| 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 | 50, 55, 60, 65, 70 and 74 | |
| 4 | 1 January 2016 | 50, 55, 60, 64, 65, 70, 72 and 74 | |
| 4 | 1 January 2017 | 50, 54, 55, 58, 60, 64, 68, 70, 72 and 74 | |
| 4 | 1 January 2018 | 50, 54, 58, 60, 62, 64, 66, 68, 70, 72 and 74 | |
| 4 | 1 January 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 incorporates all those turning the target ages from 1 January of that year onwards.
Participation in the NBCSP is measured over 2 calendar years to align with the 2-year recommended screening interval. Operationally, participation rates are calculated using an additional 6 months of data after the end of the 2-year invitation period, to allow time for all invitees to complete and return their screening kit.
Current status
In the 2-year period 2020-2021, 40.9% of invited people participated in the NBCSP,1 which was lower than the 43.8% participation in the previous rolling 2-year period (2019–2020). Female invitees had a higher participation rate (42.8%) than male invitees (38.9%).1 Participation increased with age from 31.6% for people aged 50–54 years to 52.2% for people aged 70–74 years, and were higher in those who had previously participated in the program. The participation rate was higher for people receiving their second, third or later screening invitation (43%) than those receiving their first invitation (30%) in 2020-2021. Those who had participated in their previous invitation round had a re-participation rate of 81.0%, compared with 74.0% for those who had ever previously participated.1
Remoteness and socioeconomic status (SES)
For the period of 2020-2021, participation rates varied by remoteness, with the highest rate for people living in Inner regional areas (43.4%) and the lowest for people living in Very remote areas (25.3%).
The participation rate also varied by socioeconomic status. People living in the highest socioeconomic areas had the highest participation rate (44.7%), whereas the lowest rate applied to those living in the lowest socioeconomic areas (36.6%).
International
Comparable international data for colorectal cancer screening participation are not available, due to differences in screening processes and target populations.
Trends
From 2007-2008, the colorectal cancer screening participation rate decreased from 44.0% to the lowest of 36.1% in 2012-2013, then increased to 43.8% in 2019-2020, but then decreased to 40.9% in 2020-2021.1,5 Reasons for increases may include a growing proportion of participants that had previously participated in the NBCSP, higher participation rates with increases in age, and potentially, a growing awareness of the need for screening. The program has widened its target ages in phases, resulting in a steady increase in numbers of invitees over time. The participation rate reduced from 43.8% in 2019–2020 to 40.9% in 2020–2021,4 which may reflect the impact of the COVID-19 pandemic.
The participation rate increased in all age groups from 2014-2015 to 2019-2020 with the largest increase occurring in people aged 65-69 years from 43.5% to 53.9%, then decreased in 2020-2021.5 The same trend was found in both males and females.
Remoteness and socioeconomic status (SES)
Trend data for participation by residential remoteness and socioeconomic status are available from 2013–2014 to 2019–2020. Over these periods, the participation rate in each remoteness area increased from 2013 to 2015, with a plateau from 2015 to 2017, and then an increase generally occurring to 2020, except for a decrease in Very remote/Remote and Outer regional areas from 2018-2019 to 2019-2020, potentially reflecting the impact of COVID-19.1 This rate decreased between 2019-2020 and 2020-2021 in all remoteness areas, reflecting the impact of COVID-19.
From 2013-2014 to 2019-2020, the participation rate increased in all socioeconomic groups. This rate decreased from 2019-2020 to 2020-2021 in all socioeconomic groups, from 40.4% to 36.6% in the most disadvantaged group and from 46.8% to 44.7% in the highest socioeconomic group.
Colorectal cancer control in Australia
Since the initial demonstration (pilot) projects for national colorectal cancer screening, and the subsequent years of implementation of the NBCSP, improvements have been observed in mortality and survival outcomes. The age-standardised colorectal cancer mortality rate decreased per 100,000 persons from 22.6 deaths in 2006 to 17.3 in 2018. Between the periods 2004-2008 and 2014–2018, the 5-year relative survival from bowel cancer for people aged 50–74 years at diagnosis rose from 64.8% to 70.6%.7 As Australian Cancer Database 2019, this survival rate also increased from 52.1% in 1985-1989 to 74.7% in 2015-2019.1
Data linkage studies have indicated that, compared with bowel cancers in people who were never invited to screen, screen-detected bowel cancers were associated with a 59% lower risk of death from bowel cancer. People diagnosed with screen-detected bowel cancers were less likely to die, and those who did die were less likely to die from bowel cancer, than applying to people whose bowel cancer was not screen-detected (note: 65.8% of deaths in people diagnosed with a screen-detected bowel cancer were due to bowel cancer, compared with a corresponding 78.1% in people never-invited to screen). Even after adjustment for lead-time bias, people whose bowel cancer was detected through the National Bowel Cancer Screening Program had a 40% lower risk of dying from bowel cancer than individuals whose bowel cancer was diagnosed in the absence of an invitation to screen.8
Higher survival from screen-detected bowel cancers is likely to be due to cancer diagnosis at an earlier stage. Both the AIHW report9 and a recent study evaluating the National Bowel Cancer Screening Program in South Australia10 found that screen-detected bowel cancers were more likely to be diagnosed at an earlier stage (as rated by degree of spread and reported metastases).
The proportion of people diagnosed with a localised (least advanced) bowel cancer was 30.0% for NBCSP invitees compared with 27.9% for those who were never invited to participate in the NBCSP between 2006 and 2010.9
In general, bowel cancers detected through the National Bowel Cancer Screening Program experience higher survival outcomes. Modelling indicates that the National Bowel Cancer Screening Program will prevent 92,200 cancers and 59,000 deaths over the period 2015–2040 with the current participation rate of 40%, but with potential to save 83.800 lives over this period if screening coverage can be increased to 60%. The NBCSP has been found to be cost-effective due to the cancer treatment costs averted.11
In 2018–2019, the Australian Government Department of Health and Aged Care funded the Menzies School of Health Research to develop the National Indigenous Bowel Screening Pilot. The pilot ran for 12 months from 1 November 2018 to 31 October 2019. In this pilot, an alternative screening participation pathway was used whereby primary health care centres promoted the NBCSP to their eligible Indigenous patients, distributed the NBCSP screening kits, and supported patients to participate in bowel screening. Health centres were also given the flexibility to incorporate bowel screening into their practice to suit their local circumstances and were encouraged to embed NBCSP bowel screening in routine practice. Screening participation through this Alternative Pathway (39.8%) was reported to be significantly higher than for Indigenous people using the usual pathway (23.3%).12
About the data
This measure shows the proportions of eligible persons who were invited to participate in the NBCSP and who returned a completed FOBT screening kit for analysis.
Numerator: Number of eligible persons invited in a 2-year period who returned a completed FOBT screening kit for analysis within that period or by 30 June the following year.
Denominator: Number of eligible persons who were invited to return a FOBT screening kit for analysis in a 2-year period.
Methodology
Remoteness
Participants were allocated to a remoteness area using the postcode supplied at the time of screening, using the Australian Statistical Geography Standard (ASGS). For 2018, 2019 and 2020 data, the 2016 ASGS was used; for earlier years, the 2011 ASGS was used.
Socioeconomic status
Participants were allocated to a socioeconomic group using their residential postcode according to the Socio-Economic Indexes for Areas (SEIFA) Index of Relative Socio-Economic Disadvantage (IRSD). Data from 2017 onwards used the 2016 IRSD; for earlier years the 2011 IRSD was used.
Data caveats
The NBCSP program began in 2006, offering screening to people aged 55 and 65 years, and was subsequently expanded to include other ages. In 2014, the Australian Government announced that the program would be extended to offer free 2-yearly screening for all Australians aged 50–74 years. The extension was completed in 2020.1
Monitoring reports before 2016 analysed participation differently from the indicator used in this report.
To allow trends to be compared over time, the new participation indicator specifications have been applied retrospectively to earlier years of program data within the 2023 National Bowel Cancer Screening Report.1
The performance indicators in the 2023 National Bowel Cancer Screening report1 use data collected for the NCSR (January 2020 to December 2023). However, this report also summarizes trends from 2007–2008 to 2020–2021 in program participation rate, diagnostic assessment rate, and time between positive screen and diagnostic assessment. These trends use data collected for the NBCSP Register as well as data collected for the NCSR.
Data sources
Australian Institute of Health and Welfare 2023. National Bowel Cancer Screening program monitoring report 2023. Cat. no. CAN 154. Canberra: AIHW. Accessed June 2023; https://www.aihw.gov.au/reports/cancer-screening/nbcsp-monitoring-2023/data
Australian Institute of Health and Welfare 2023. Cancer screening programs: quarterly data. Cat. no. CAN 114. Canberra: AIHW. Accessed June 2023. https://www.aihw.gov.au/reports/cancer-screening/national-cancer-screening-programs-participation/data
Australian Institute of Health and Welfare 2022. National Bowel Cancer Screening Program: monitoring report 2022. Cat. no. CAN 148. Canberra: AIHW.
Australian Institute of Health and Welfare 2021.National Bowel Cancer Screening Program: monitoring report 2021. Cat. no. CAN 139. Canberra: AIHW.
Australian Institute of Health and Welfare 2020.National Bowel Cancer Screening Program: monitoring report 2020. Cat. no. CAN 133. Canberra: AIHW.
Australian Institute of Health and Welfare 2019.National Bowel Cancer Screening Program: monitoring report 2019. Cat. no. CAN 125. Canberra: AIHW.
Australian Institute of Health and Welfare 2018.National Bowel Cancer Screening Program: monitoring report 2018. Cat. no. CAN 112. Canberra: AIHW.
Australian Institute of Health and Welfare 2017.National Bowel Cancer Screening Program: monitoring report 2017. Cat. no. CAN 103. Canberra: AIHW.
Australian Institute of Health and Welfare 2016.National Bowel Cancer Screening Program: monitoring report 2016. Cat. no. CAN 97. Canberra: AIHW.
References
- Australian Institute of Health and Welfare 2023. National Bowel Cancer Screening program monitoring report 2023. Cat. no. CAN 154. Canberra: AIHW. Accessed June 2023; https://www.aihw.gov.au/reports/cancer-screening/nbcsp-monitoring-2023/summary
- Cancer Australia 2022. Bowel cancer statistics. Cancer Australia 2022. Accessed March 2023; https://www.canceraustralia.gov.au/cancer-types/bowel-cancer/statistics#:~:text=In%202020%2C%20bowel%20cancer%20was,2%2C847%20males%20and%202%2C507%20females
- Australian Institute of Health and Welfare 2022. Cancer Data in Australia. Cancer rankings data visualisation. Accessed March 2023; https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-rankings-data-visualisation
- Hewitson P et al. Cochrane systematic review of colorectal cancer screening using the fecal occult blood test (hemoccult): an update. Am J Gastroenterol. 2008 Jun;103(6):1541-9. doi: 10.1111/j.1572-0241.2008.01875.x.
- Australian Institute of Health and Welfare 2023. Cancer screening programs: quarterly data. Cat. no. CAN 114. Canberra: AIHW. Accessed May 23; https://www.aihw.gov.au/reports/cancer-screening/national-cancer-screening-programs-participation/contents/about
- Australian Institute of Health and Welfare 2022. Cancer Data in Australia. Cancer mortality by age visualisation. Accessed March 2023; https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-mortality-by-age-visualisation
- Australian Institute of Health and Welfare 2022. Cancer Data in Australia. Cancer survival data visualisation. Accessed March 2023; https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-survival-data-visualisation
- Australian Institute of Health and Welfare 2018. Analysis of cancer outcomes and screening behaviour for national cancer screening programs in Australia. Cat. no. CAN 115. Canberra: AIHW. Accessed March 23; https://www.aihw.gov.au/reports/cancer-screening/cancer-outcomes-screening-behaviour-programs/summary
- Australian Institute of Health and Welfare 2018. Analysis of bowel cancer outcomes for the National Bowel Cancer Screening Program. Cat. no. CAN 113. Canberra: AIHW. Accessed March 23; https://www.aihw.gov.au/reports/cancer-screening/analysis-of-bowel-cancer-outcomes-nbcsp-2018/summary
- Cole SR, Tucker GR, Osborne JM, et al. Shift to earlier stage at diagnosis as a consequence of the National Bowel Cancer Screening Program. Med J Aust. 2013 Apr 1;198(6):327-30. doi: 10.5694/mja12.11357.
- Lew JB, St John DJB, Xu XM, et al. Long-term evaluation of benefits, harms, and cost-effectiveness of the National Bowel Cancer Screening Program in Australia: a modelling study. Lancet Public Health 2:e331–e340.
- Australian Government of Health and Aged Care. Final report on the National Indigenous Bowel Screening Pilot. Accessed March 2023; https://www.health.gov.au/resources/publications/final-report-on-the-national-indigenous-bowel-screening-pilot?language=en