National Bowel Cancer Screening Program monitoring report 2025

PI 9 – Adverse events – hospital admission

The following apply to the 69,914 people who had a diagnostic assessment in 2023:

Australia-wide: Three people were admitted to hospital within 30 days of assessment, giving an overall Australia-wide hospital admission rate after assessment of 0.4 per 10,000 assessments (Table A3.37). Reporting of adverse events after a NBCSP colonoscopy is required (ACSQHC 2020), but not mandated by the NBCSP. So this rate may be underestimated.

Due to concerns about the level of data completeness, no other disaggregations are presented for this indicator.

PI 10 – Incidence of bowel cancer

The following estimates were calculated for 2024:

Australia-wide: A total of 7,265 people aged 50–74 will be diagnosed with bowel cancer, giving an age-standardised rate of 96 new cases per 100,000 people (Table A3.38).

Sex: Of people aged 50–74, men will be more likely to be diagnosed with bowel cancer than women (120 new cases per 100,000 males compared with 82 new cases per 100,000 females). When age standardised, rates for males and females will be 114 and 78 new cases, respectively, per 100,000 (Table A3.38).

Age: Bowel cancer incidence rates will be higher for older age groups. For people in the target age group, the estimated bowel cancer incidence rate will increase with increasing age, from 63 new cases per 100,000 people aged 50–54 to 180 new cases per 100,000 people aged 70–74 (Figure 3.27).

Trend: Among people aged 50–74, the number of new bowel cancer cases per year rose from 4,384 in 1982 to a peak of 8,217 in 2010. The number of new cases per year has declined since then to an estimated 7,265 in 2024. The age-standardised rate for new cases (per 100,000 people aged 50–74) rose from 138 in 1982 to a peak of 164 in 1996 (Figure 3.28). Since then, the rate has fallen, and the ASR is estimated to be 96 new cases per 100,000 in 2024. The ASRs for new bowel cancer are expected to continue to decline.

Note that bowel cancers diagnosed after a positive NBCSP screen are shown separately in Figure 3.28, and have increased from 2006 as the rollout of the eligible NBCSP target ages were added (completed in 2020).

State or territory: In the period 2016–2020, the rate of new cases of bowel cancer per 100,000 people aged 50–74 was highest in Queensland (124 new cases of bowel cancer per 100,000 people) and lowest in Western Australia (101 new cases per 100,000 people) (Table A3.39). The age-standardised rates by state or territory followed a similar pattern to the crude rates (Figure 3.29).

Remoteness area: In the period 2016–2020, incidence of bowel cancer per 100,000 people aged 50–74 differed by remoteness area. Age-standardised rates (ASR) are shown in Figure 3.30a and below.

The ASR for new cases of bowel cancer per 100,000 people aged 50–74 was highest for those living in Remote areas (128 new cases of bowel cancer per 100,000 people) and lowest for people living in Very remote areas (98 new cases per 100,000 people) (Figure 3.30a).

Socioeconomic area: In the period 2016–2020, incidence of bowel cancer per 100,000 people aged 50–74 differed by socioeconomic area. Age-standardised rates are shown in Figure 3.30b and below.

The ASR for new cases of bowel cancer per 100,000 people aged 50–74 was highest for those living in the lowest socioeconomic areas (126 new cases of bowel cancer per 100,000 people) and lowest for people living in the highest socioeconomic areas (96 new cases per 100,000 people) (Figure 3.30b).

Aboriginal and/or Torres Strait Islander people: Reliable national data on the diagnosis of cancer for Indigenous Australians are not available. All state and territory cancer registries collect information on Indigenous status; however, in some jurisdictions, the quality of the data is insufficient for analysis. Information in the ACD on Indigenous status is considered to be of sufficient completeness for reporting for New South Wales, Victoria, Queensland, Western Australia, the Australian Capital Territory, and the Northern Territory.

While the majority (91%) of Indigenous Australians live in these 6 jurisdictions, the degree to which data for these jurisdictions are representative of data for all Indigenous Australians is unknown (ABS 2017). For the 6 jurisdictions analysed, 3% (1,214 records) of the relevant ACD records had unknown Indigenous status for bowel cancer diagnoses for people aged 50–74 in 2016–2020 (Table A3.40).

The incidence counts and rates for Indigenous and non-Indigenous Australians presented are under-estimated due to the relatively large proportion of people whose Indigenous status is not stated, or not available. Also, it is likely that some Indigenous Australians are misclassified as non-Indigenous Australians. Therefore, the estimates presented in this report should be interpreted with caution. In addition, age-standardised incidence rates should be used to compare the incidence of bowel cancer for Indigenous and non-Indigenous Australians to account for the different age structures of Indigenous and non-Indigenous populations. See Box 3.1 for information on Indigenous rates calculated using Indigenous population estimates from the 2016 Census.

Based on the data from the 6 jurisdictions analysed, Indigenous Australians aged 50–74 had a crude rate of incidence of bowel cancer of 112 per 100,000. Following adjustment for differences in the age structure between the two population groups, Indigenous Australians had a higher incidence rate than non-Indigenous Australians in 2016–2020 (122 and 110 cases, respectively, per 100,000 people) (Figure 3.31).

PI 11 – Mortality from bowel cancer

The following estimates were calculated for 2024:

Australia-wide: A total of 1,793 people aged 50–74 will die from bowel cancer, giving an age-standardised rate of 23 deaths per 100,000 people (Table A3.42).

Sex: Males aged 50–74 will be more likely to die from bowel cancer than females (30 deaths per 100,000 males compared with 20 deaths per 100,000 females) (Figure 3.32). When age standardised, rates for males and females will be 28 and 19 deaths, respectively, per 100,000 (Table A3.42).

Age: The bowel cancer mortality rate will continue to be higher for older age groups (Table A3.42). For people in the target age range, the estimated bowel cancer mortality rate per 100,000 people will rise from 12 deaths for those aged 50–54 to 48 deaths for those aged 70–74 (Figure 3.32).

Trend: Since 1987, the age-standardised mortality rate from bowel cancer per 100,000 people aged 50–74 has fallen from 69 to an estimated 23 deaths per 100,000 in 2024 (Figure 3.33). The number of deaths from bowel cancer peaked at 2,623 cases in 1994 and decreased to an estimated 1,793 in 2024. The overall effect of the increasing and ageing Australian population is that, while the age-standardised mortality rate has steadily fallen over time, the actual number of deaths has remained stable or slowly declined.

The NBCSP started in 2006 and, from 2020, rollout of biennial screening for all eligible Australians in the current target age group (50–74) was in effect. Once biennial invitations have been in place for a number of years, and actual mortality data are available for 2022 onwards, it will be easier to quantify the program’s impact on bowel cancer mortality. However, studies conducted by the AIHW of people diagnosed with bowel cancer in 2006–2008 showed that NBCSP invitees (particularly those who participated) diagnosed with bowel cancer had less risk of dying from the disease and were more likely to have less advanced cancers when diagnosed than non‑invitees. These findings provide evidence that the NBCSP is contributing to reducing morbidity and mortality from bowel cancer in Australia (AIHW 2014b, 2018a, 2018b).

State or territory: In 2018–2022, the mortality rate per 100,000 people aged 50–74 was highest in Tasmania (33 deaths from bowel cancer) and lowest in the Australian Capital Territory (23 deaths) (Table A3.43). The age-standardised rates by state or territory followed a generally similar pattern to the crude rates (Figure 3.34).

Remoteness area: In the period 2018–2022, mortality from bowel cancer per 100,000 people aged 50–74 differed by remoteness area. Age-standardised rates are shown in Figure 3.35a and below.

The ASR per 100,000 people aged 50–74 was highest for those living in Outer regional areas (32 deaths from bowel cancer) and lowest for those living in Very remote areas 
 (21 deaths) (Figure 3.35a).

Socioeconomic area: In the period 2018–2022, mortality from bowel cancer per 100,000 people aged 50–74 differed by socioeconomic area. Age-standardised rates are shown in Figure 3.35b and below.

The ASR per 100,000 people aged 50–74 was highest for those living in the lowest socioeconomic areas (32 deaths from bowel cancer) and lowest for those living in the highest socioeconomic areas (20 deaths) (Figure 3.35b).

Aboriginal and/or Torres Strait Islander people: Age-standardised mortality rates should be used to compare the mortality rate from bowel cancer between Indigenous and non-Indigenous Australians to account for the different age structures between the 2 populations. Only mortality data from New South Wales, Queensland, Western Australia, South Australia, and the Northern Territory are considered adequate for reporting by Indigenous status. Other jurisdictions have a small number of Indigenous deaths, and identification of these in their death registration systems is relatively poor, making the data less reliable. Note that these jurisdictions differ from those used to calculate incidence for Indigenous and non-Indigenous Australians (see Box 3.1).

For the period 2018–2022, 234 Indigenous Australians aged 50–74 died from bowel cancer in Australia, with 210 of these deaths registered in New South Wales, Queensland, Western Australia, South Australia, and the Northern Territory.

In these jurisdictions for the period 2018–2022, Indigenous Australians aged 50–74 had a crude mortality rate of 36 deaths per 100,000. Following adjustment for differences in age structure between the two population groups, mortality from bowel cancer was higher for Indigenous Australians compared with non‑Indigenous Australians (ASRs per 100,000 people of 39 and 27 deaths, respectively, from bowel cancer) (Figure 3.36).