The National Bowel Cancer Screening Program (NBCSP) began in 2006. Its goal is to reduce illness and deaths caused by bowel cancer (also known as colorectal cancer). Screening helps detect cancers and pre-cancerous growths early, when treatment is most likely to be successful.1,2
The bowel screening test is an Immunochemical faecal occult blood test (iFOBT), which is a non-invasive screening method that detects microscopic traces of blood in bowel motion samples.
Eligible Australians (those aged 50–74 years) are sent a free iFOTB screening kit and are invited to screen every 2 years. It is now recommended that asymptomatic Australians aged 45 years and over also undergo bowel screening every two years. In line with this recommendation, starting from 1 July 2024, Australians aged 45–49 years are also eligible for the program. They can request their first kit through the program or by speaking with their doctor.1,2
One of the indicators of program performance is the proportion of the invited eligible population who return 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 Increases in participation rates for bowel cancer screening rates by at least 53% by 2025 is one of the focus areas of National Preventive Health Strategy 2021-2030.3
About this measure
In 2024, Bowel cancer was estimated to become the fourth most common cancer recorded in Australia.4 The age-standardised incidence rate (based on the 2024 Australian population) is estimated at 57.2 cases per 100,000 people. This rate is only exceeded by rates for prostate cancer, breast cancer, and melanoma of the skin.5
Colorectal cancer was also estimated to remain the second leading cause of cancer-related deaths in Australians of all ages, after lung cancer. In 2024, the death rate is projected to be 19.3 per 100,000 people.4,6
Among people aged 50–74 years, approximately 7,265 are expected to have been newly diagnosed with colorectal cancer in 2024. This accounts for 46.7% of all colorectal cancers diagnosed. Additionally, 1,793 people in this age group are expected to die from the disease, making up 34.2% of all colorectal cancer deaths.5,6
Bowel cancer can be present for many years before showing symptoms. Symptoms are often 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. This relatively slow development of bowel cancer provides opportunity for early detection and effective treatment of precancerous polyps/adenomas and early-stage cancers.1
An immunochemical faecal occult blood test (iFOBT) is commonly used for 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 (i.e., adenoma or cancer). FOBT screening reduces the risk of colorectal cancer mortality.7
The two-yearly screening in the National Bowel Cancer Screening Program (NBCSP) was fully implemented from 2020. Phases in the preceding roll-out and the target populations are shown below.
Eligible Australians receive free iFOBT kits, starting at age 50 years. Invitations are then sent every two years after they have completed their last test, until age 74 years. The population screening protocol was revised in 2023, recommending that biennial iFOBT screening for the asymptomatic Australian population be offered from age 45 years and continued to age 74 years. From 1 July 2024, eligible people aged 45–49 years can request their first NBCSP kit from the program, or by talking to their doctor.8 This change in clinical guidance did not yet apply in the time period addressed in this NBCSP 2024 report.
The phased introduction of bowel cancer screening was as follows1:
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 | 31 December 2014
| 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 and74 |
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 | 30 June 2024 | 50, 52, 54, 56, 58,60, 62, 64, 66, 68, 70, 72 and 74 |
5 | 1 July 2024 | Ongoing | People aged 50–74 continue to receive a NBCSP kit every 2 years. People aged 45–49 can request their first NBCSP kit |
Eligible birth dates, and thus invitations, ended on 31 December 2010.
Ongoing NBCSP funding commenced.
Note: The eligible population for all Phase 2 and 3 start dates incorporates all those turning the target ages from 1January 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.1
Current status
In the 2-year period 2021-2022, 40.0% of invited people aged 50-74 years participated in the NBCSP1. This was similar to the 40.9% participation in the previous rolling 2-year period (2020–2021).Female invitees had a higher participation rate (42.1%) than male invitees (38.0%).1 Participation increased with age from 31.2% for people aged 50–54 years to 38.2% for those aged 55-59 years, 40.6% for those aged 60-64 years, and 50.2% for people aged 70–74 years.
The participation rate was higher for people receiving their subsequent [TN1] screening invitation (41.3%) than those receiving their first invitation (30.9%) in 2021-2022. People were more likely to participate in a screening round if they had also participated in the previous two years. Those who had participated in the previous two years had a re-participation rate of 81.1%. This compared with 72.4% for those who had ever previously participated.1
Remoteness and socioeconomic status (SES)
For the period of 2021-2022, participation rates varied by remoteness, with the highest rate for people living in inner regional areas (42.2%) and the lowest for people living in very remote areas (25.5%).1
The participation rate increased with increasing socioeconomic status. People living in the highest socioeconomic areas had the highest participation rate (44.6%), whereas those living in the lowest socioeconomic areas had the lowest rate (35.0%).1
Trends
From 2007-2008 to 2012-2013, the NBCSP participation rate decreased from 44.0% to 36.1%. Since the expansion of the program in 2014, this rate increased from 38.9% in 2014-15 to 43.8% in 2019-2020. It then decreased slightly to 40.9% in 2020-2021 and remains at 40.0% in 2021-2022.1
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.1 The participation rate declined since 2020 which may have been influenced by the COVID-19 pandemic. The same trend was found in males and females.
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%. 1
Colorectal cancer control in Australia
Since the implementation of the NBCSP, improvements have been observed in mortality and survival outcomes. The age-standardized (footnote) colorectal cancer mortality rate has substantially decreased from 30.2 deaths per 100,000 persons in 2006 to an estimated 19.3 deaths per 100,000 in 2024.6 Between the periods of 2001-2005 and 2016–2020, the 5-year relative survival recorded from bowel cancer rose from 63.0% to 71.3%.9
An AIHW analysis in 2018 found that even after adjustment for lead-time effects, people whose bowel cancer was detected through the NBCSP had a 40% lower risk of dying from bowel cancer than individuals who had never been invited to screen.10 The all-cause mortality risk was found to be 7% higher for non-invitees.11
Higher survival from screen-detected bowel cancers is likely to be due to cancer diagnosis at an earlier stage. Both the AIHW report11 and a recent study evaluating the National Bowel Cancer Screening Program in South Australia12 found that screen-detected bowel cancers were more likely to be diagnosed at an earlier stage (as indicated by degree of spread and reported metastases). For the 2006-2010 of NBCSP participants with screen-detected bowel cancer, 44% had their cancer detected at a local (least advanced) stage. In comparison, only 24% of non-responders had their cancer detected at this early stage.11
In general, bowel cancers detected through the National Bowel Cancer Screening Program (NBCSP) 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%, with the 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.13
First Nations Bowel Screening Outcomes
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 First Nations 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 in a manner that suited their local circumstances. They were also encouraged to embed NBCSP bowel screening in routine practice.Screening participation through this Alternative Pathway (39.8%) was reported, which was significantly higher than for First Nations people using the usual pathway (23.3%).14
Footnote: (to 2024 Aus. Standardisation population)
About the data
This measure shows the proportions of eligible persons invited to participate in the NBCSP who returned a completed screening test for analysis.
Numerator: Number of eligible persons invited in a 2-year period who returned a completed screening test for analysis within that period or by 30 June the following year (i.e., between 1 January 2021 and 31 December 2022 or by 30 June 2023 for the period of 2021-2022).1
Denominator: Number of eligible persons who were invited to screen through the NBCSP in a 2-year period.
The NBCSP Register data were transitioned from the NBCSP Register, maintained by Services Australia (formerly the Department of Human Services), to the National Cancer Screening Register (NCSR), maintained by Telstra Health from November 2019.1The NCSR is a live database which is updated over time such that later reports using these data may have a greater level of completeness.
To participate in the NBCSP, invitees completed the screening test and posted it to NBCSP pathology laboratory for analysis. Results were sent to the participant, the participant’s nominated primary health-care practitioner (PHCP), and the NCSR.1 NBCSP monitoring reports use data extracted from the NCSR. These data are sourced from live databases that are updated over time and may differ from other AIHW cancer screening reports where the data are sourced at a different time.1
The performance indicators in NBCSP 2024 report use data collected for the NCSR (January 2021 to December 2023). However, data for the trend used data collected for the NBCSP Register as well as data collected for the NCSR.1Monitoring reports from 2016 onwards differ from those released earlier and participation was analysed differently from the indicator used in this NBCSP 2024 report.1 To allow trends to be compared over time, the new participation indicator specifications have been applied retrospectively to earlier years of program data within this report.1 For a full summary of changes to the performance indicators, reporting period, and structure of the report since 2016, please see National Bowel Cancer Screening Program monitoring report 2019.
Methodology
Remoteness
Participants were allocated to a remoteness area indicated by their residential postcode supplied at the time of screening, using the Australian Statistical Geography Standard (ASGS).
For the 2024 report, participants’ residential addresses by Statistical Area Level 2 were mapped according to the 2021 Australian Statistical Geography. As some Statistical Area Level 2 areas can span different Remoteness Areas, a weighting for each Remoteness Area was used to attribute cases across these Statistical Areas (Level 2). This can result in non-integer counts for remoteness classifications. From NBCSP Monitoring reports 2020, postcodes of participants were mapped to the 2016 Australian Statistical Geography Standard Remoteness Areas. For earlier years, the 2011 ASGS was used.1
Socioeconomic status
Participants were allocated to a socioeconomic group using the Statistical Area Level 2 of the participant’s residential address according to the Index of Relative Socio-economic Disadvantage (IRSD). The Index of Relative Socio-economic Disadvantage (IRSD) is a general socio-economic index that summarizes a range of information about the economic and social conditions of people and households within an area. Socioeconomic groupings (based on IRSD rankings) were calculated with a Statistical Area Level 2 correspondence, using a population-based method at the Australia-wide level. Data from NBCSP Monitoring reports 2019 onwards were classified using the IRSD for 2016; for earlier years, the IRSD for 2011 was used.1
Data caveats
For NBCSP reports before 2016, participation was analysed differently from that in this 2024 report. This means that trend comparisons with rates published in earlier reports should not be made. 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 2024 National Bowel Cancer Screening Report.1
Invitations issued to the target age group population in the NBCSP exclude those without a valid mailing address in the NCSR (177,173 people).1The number of invitations sent excludes those who deferred/opted out without completing screening tests and those who skipped an invitation round due to a recent colonoscopy (in the last 2 years). This proportion was 8.2% in the period 2021–2022.1
There were limitations in the data available to estimate Indigenous Australians’ participation in the NBCSP, due to differences in the ‘not stated’ proportions between the 2021–2022 NBCSP participation data and the 2021 Census data (3.6% and 4.5% ‘not stated’, respectively).1 NBCSP participants can self-identify as being an Aboriginal and/or Torres Strait Islander person by completing and returning the participant details form along with their iFOBT for analysis. The NCSR uses self-reporting from the participant details form and the Medicare Voluntary Indigenous Identifier, along with other sources such as the National Cervical Screening Program (for invitees who participate in cervical screening) to assign Indigenous status. These sources are still not sufficient to reliably identify membership of these subgroups for all invitees. Also, it is likely that some Indigenous Australians are misclassified as non-Indigenous Australians. Therefore, these estimates presented should be interpreted with caution.
Data sources
Australian Institute of Health and Welfare 2024. National Bowel Cancer Screening program monitoring report 2024. Cat. no. CAN 160. Canberra: AIHW. Accessed Nov 2024; https://www.aihw.gov.au/reports/cancer-screening/nbcsp-monitoring-2024/data
Australian Institute of Health and Welfare 2023. National Bowel Cancer Screening program monitoring report 2023. Cat. no. CAN 154. Canberra: AIHW. Accessed Nov 2024; https://www.aihw.gov.au/reports/cancer-screening/nbcsp-monitoring-2023/data
Australian Institute of Health and Welfare. National bowel cancer screening program monitoring reports. Report Editions. Accessed Nov 2024; https://www.aihw.gov.au/reports/cancer-screening/nbcsp-monitoring-2024/report-editions
References
Australian Institute of Health and Welfare 2024. National Bowel Cancer Screening program monitoring report 2024. Cat. no. CAN 160. Canberra: AIHW. Accessed Nov 2024;https://www.aihw.gov.au/reports/cancer-screening/nbcsp-monitoring-2024/summary
Australian Government. Department of Health and Aged Care 2024. National Bowel Cancer Screening Program. Accessed Nov 2024; https://www.health.gov.au/our-work/national-bowel-cancer-screening-program
Australian Government. Department of Health and Aged Care 2021. National Preventive Health Strategy 2021-2030.Accessed Nov 2024; https://www.health.gov.au/resources/publications/national-preventive-health-strategy-2021-2030?language=en
Australian Institute of Health and Welfare 2024. Cancer Data in Australia. Cancer rankings data visualisation. Accessed Nov 2024; https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-rankings-data-visualisation
Australian Institute of Health and Welfare 2024. Cancer Data in Australia. Cancer incidence by age visualisation. Accessed Nov 2024; https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-incidence-by-age-visualisation
Australian Institute of Health and Welfare 2024. Cancer Data in Australia. Cancer mortality by age visualisation. Accessed Nov 2024;https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-mortality-by-age-visualisation
Hewitson P, Glasziou P, Watson E, 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.
Cancer Council Australia 2024. Screening. Bowel Cancer Early Detection Policy. Accessed Nov 2024; https://www.cancer.org.au/about-us/policy-and-advocacy/early-detection/bowel-cancer/screening
Australian Institute of Health and Welfare 2024. Cancer Data in Australia. Cancer survival by age visualisation. Accessed Nov 2024; https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-survival-by-age-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 Nov 2024; 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 Nov 2024;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.
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. Department of Health and Aged Care 2022. Final report on the National Indigenous Bowel Screening Pilot. Accessed Nov 2024; https://www.health.gov.au/resources/publications/final-report-on-the-national-indigenous-bowel-screening-pilot?language=en