Summary
It is estimated that in 2024 about 7,265 people aged 50–74 were diagnosed with bowel cancer (around 47% of all bowel cancers diagnosed) and 1,793 people in this age group died from the disease (around 34% of all bowel cancer deaths).
The National Bowel Cancer Screening Program (NBCSP) began in 2006. It aims to reduce the morbidity and mortality from bowel cancer by actively recruiting and screening the target population, aged 50–74, for early detection or prevention of the disease.
This report presents the latest data against the NBCSP key performance indicators (AIHW 2014). While the latest data are to December 2024, the year for which each performance indicator are reported can vary to ensure that the most recent data are used for each indicator.
Note that, while outside the 2022–2023 reporting period in this report, from 1 July 2024, those aged 45–49 were eligible to request a screening kit; some initial information on this cohort is provided in this report.
How many people participated?
Of the 6.3 million people invited between January 2022 and December 2023, 41.7% participated in the program. The national participation rate was higher than the previous rolling
2-year period (40.0% in 2021–2022). The re-participation rate for those who took part in their previous invitation round and received a subsequent screening invitation was 83.0%. For those who had ever previously participated, the re-participation rate was 73.4%.
Screening results in 2023
In 2023, 86,089 Australians returned a positive screening test, giving a 6% screening positivity rate. Of those who received a positive screening test, 86% reported a follow-up diagnostic assessment. The median time from positive screening test result to diagnostic assessment was 62 days.
New information in this report
Colonoscopy outcomes should be provided to the NBCSP (ACSQHC 2020), but as form return is not mandated by the NBCSP, diagnostic assessment data are generally not considered complete enough to allow formal performance indicator reporting. However, in this report, for the first time, NBCSP records have been matched to national cancer diagnosis data (to 2020 only). The result of this is that bowel cancer diagnoses related to NBCSP participation in 2019 and earlier are now much more complete than previously, and Performance Indicators 6a (colorectal cancer detection rate), 6b (PPV of diagnostic assessment for detecting colorectal cancer), and 7 (interval cancer rate) can be reported for the NBCSP for the first time.
Cancers detected in 2019
There were 2,683 screen-detected bowel cancers diagnosed in people who participated in the NBCSP in 2019, which equates to a bowel cancer detection rate of 20.3 cancers diagnosed per 10,000 people screened (performance indicator 6a).
Cancers detection rate of colonoscopy in 2019
About 1 in 26 colonoscopies performed in 2019 to investigate a positive screening test (3.8%) returned a diagnosis of bowel cancer (performance indicator 6b).
Interval cancer rate in 2018
In the context of the NBCSP, interval cancers are bowel cancers diagnosed after completion of a negative screening test and before the next screening test or within 24 months, whichever comes first. For every 10,000 participants who had a negative screening test in 2018, 6.3 had a bowel cancer diagnosed within 2 years. This is an interval cancer rate of 6.3 bowel cancers per 10,000 participants who had a negative screen.
Cancers and adenomas detected in 2023
Matched national cancer diagnosis data were not available for those who screened later than 2019. However, of the outcome data available from program form return, for participants who had a diagnostic assessment in 2023, 1 in 26 were diagnosed with a confirmed or suspected cancer (186 and 658, respectively) and 1 in 4 were diagnosed with an adenoma (5,188 participants). Adenomas are benign growths with potential to become cancerous; their removal lowers the risk of future bowel cancers developing.
Variation across population groups
Participants who identified as being of Aboriginal and/or Torres Strait Islander origin, those who lived in Very remote areas, and those who lived in low socioeconomic areas, all had higher rates of positive screens (warranting further assessment), but lower rates of follow-up diagnostic assessment, and a longer median time between a positive screen and assessment.
Since the NBCSP began
Since the program began in August 2006, about 12.8 million NBCSP screening tests have been completed, with about 5.1 million people participating at least once. Due to the improvement in bowel cancer outcomes data in this report, it is now known that 16,809 bowel cancers have been diagnosed through screening in the NBCSP.
The AIHW has previously conducted studies of people diagnosed with bowel cancer between 2006 and 2010. These studies showed that NBCSP invitees (particularly those who participated) who were diagnosed with bowel cancer had a lower risk of dying from the disease and were more likely to have less advanced bowel cancers when diagnosed. These findings show that the NBCSP is contributing to reducing morbidity and mortality from bowel cancer in Australia (2018a, 2018b).
ACSQHC (Australian Commission on Safety and Quality in Health Care) (2020) Colonoscopy Clinical Care Standard, Australian Commission on Safety and Quality in Health Care, Sydney, accessed 14 May 2025.
AIHW (2014) Key performance indicators for the National Bowel Cancer Screening Program: technical report, AIHW, Australian Government, accessed 09 May 2022.
AIHW (2018a) Analysis of bowel cancer outcomes for the National Bowel Cancer Screening Program 2018, AIHW, Australian Government, accessed 09 May 2022.
AIHW (2018b) Analysis of cancer outcomes and screening behaviour for national cancer screening programs in Australia, AIHW, Australian Government, accessed 09 May 2022.