Colonoscopy follow-up after a positive colorectal screening test

Published

19 Dec, 2019

Australia commenced an organised program of colorectal (bowel) cancer population screening in 2006, the National Bowel Cancer Screening Program (NBCSP). Indicators of the performance of this Program, include the proportion of positive FOBT cases having a follow-up diagnostic assessment (colonoscopy), and the elapsed time between a positive FOBT and the assessment.¹ It is desirable that follow-up diagnostic assessments occur in a timely manner, thus minimising potential harms from delayed diagnosis and treatment. ¹ The data presented in this measure are for the proportion of the eligible population who had a follow-up colonoscopy recorded within 360 days of a positive FOBT result.

It should be noted that the reporting of colonoscopies to the NBCSP is not mandatory and there is an unknown degree of under-reporting that may affect the data. The data shown in this analysis are based on information recorded in the Program Register only.

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Notes

• Data sourced from AIHW National Bowel Cancer Screening Program: monitoring reports.
• Rates are not age-standardised.

Proportion of the eligible population invited who had a follow-up colonoscopy within 360 days of a positive FOBT, 2014 to 2017
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Notes

• Data sourced from AIHW National Bowel Cancer Screening Program: monitoring reports.
• Rates are not age-standardised.

Proportion of the eligible population invited who had a follow-up colonoscopy recorded within 360 days of a positive FOBT, 2017
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Notes

• Data sourced from AIHW National Bowel Cancer Screening Program: monitoring reports.
• Rates are not age-standardised.

Proportion of the eligible population invited who had a follow-up colonoscopy within 360 days of a positive FOBT, by Indigenous status and year
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Notes

• Data sourced from AIHW National Bowel Cancer Screening Program: monitoring reports.
• Rates are not age-standardised.
• Remoteness areas were allocated based on the Australian Statistical Geography Standard (ASGS) 2011.

Proportion of the eligible population invited who had a follow-up colonoscopy within 360 days of a positive FOBT, by remoteness area and year
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Notes

• Data sourced from AIHW National Bowel Cancer Screening Program: monitoring reports.
• A participant’s socioeconomic status area was classified by mapping their residential postcode (through a postal area) to the ABS IRSD for 2011. Those that could not be mapped are excluded from this analysis.
• Rates are not age-standardised.

Proportion of the eligible population invited who had a follow-up colonoscopy within 360 days of a positive FOBT, by socioeconomic status and year

About this measure

Australia has one of the highest rates of colorectal cancer in the world, and it is projected to be the third most commonly diagnosed cancer recorded in Australia in 2019 (after breast cancer and prostate cancer).¹ It is projected, that in 2019, 16,398 persons will be diagnosed with this disease, and that this cancer will cause 5,597deaths.¹ It is also estimated that colorectal cancer will remain the second leading cause of cancer death in Australia (after lung cancer).¹

Colorectal cancer may be present for many years before showing clear symptoms, but non-visible bleeding of the colon and rectum can occur in the precancerous stage.¹ The FOBT is a non-invasive test that detects microscopic amounts of blood in a faecal sample. Regular screening using the FOBT and treatment of FOBT-positive cases can reduce mortality due to colorectal cancer by up to one-third.²

A positive FOBT result requires a follow-up procedure to determine an accurate diagnosis. Colonoscopy is currently considered the most accurate procedure, because it enables biopsy and subsequent histopathological diagnosis. Colonoscopy also allows identification and endoscopic removal of polyps and adenomas.¹

In 2002, a pilot program was undertaken in Australia to test the feasibility, acceptability, and cost-effectiveness of national colorectal cancer screening. The success of this pilot program led to the Australian Government implementing:

Phase 1 of the NBCSP, which commenced in August 2006 to screen Australians of the target ages of 55 and 65 years.
Phase 2 commenced in July 2008 and screened Australians of the target ages of 50, 55 and 65 years.
Phase 3 commenced in July 2013 and screened Australians of the target ages of 50, 55, 60 and 65 years.
Phase 4 of the NBCSP commenced on 1 January 2015; in this phase the program is being gradually rolled-out over 5 years to achieve biennial screening for Australians aged 50–74 years.³

Current status

In 2017, 66.1% of the eligible invited population, who returned a positive (abnormal) result from a correctly completed FOBT screening kit, had a follow-up colonoscopy recorded within 360 days of their screening result.¹ Rates were slightly higher among females (67.0%) than among males (65.4%), and were higher among younger persons (50–54, 68.0%) than among older persons (70–74, 64.9%).¹

Aboriginal and Torres Strait Islander peoples

In 2017, the colonoscopy follow-up rate within 360 days were lower among Indigenous Australians (51.0%) than among non-Indigenous Australians (66.5%).¹

Remoteness and socioeconomic status (SES)

In 2017, the colonoscopy follow-up rate within 360 days varied by remoteness area, with the highest rates occurring in Major Cities (70.3%), and the lowest rates occurring in Very Remote areas (53.0%).¹ The colonoscopy follow-up rate within 360 days also varied by socioeconomic status, ranging from 59.3% for the lowest socioeconomic status area (SES 1) and 60.8% for the second lowest socioeconomic status area (SES 2) to 74.2% for the highest socioeconomic status area (SES 5).¹

It should be noted that as reporting of follow-up assessments is not mandatory, there is an unknown level of under-reporting and that levels of under-reporting may differ across population groups.¹ Comparable international data for colonoscopy follow-up rates are not available, due to differences in screening processes and target populations.

Trends

Trend data for the colonoscopy follow-up rate within 360 days are available for the years 2014 to 2017. Over this period the rate decreased from 73.1% to 66.1%. Similar trends were observed for both sexes, and in each group in the target age range.¹

Changes in the reporting process for follow-up colonoscopies, as well as changes in diagnostic assessment pathway practices between years, may be factors contributing to this observed decrease.¹ It should also be noted that this indicator relies on information being reported to the Program Register; however, this is not mandatory, leading to incomplete data.

Aboriginal and Torres Strait Islander peoples

From 2014 to 2017, the colonoscopy follow-up rate within 360 days decreased among Indigenous Australians from 58.5% to 51.0%. A similar decrease was observed for non-Indigenous Australians, for whom the rate decreased from 73.7% to 66.5%.^{1, 4-6}

Remoteness and socioeconomic status (SES)

From 2014 to 2017, the colonoscopy follow-up rate within 360 days decreased across all socioeconomic status areas.^{1, 4-6} The largest decreases in colonoscopy follow-up rates were in SES 1 and 2.

From 2015 to 2017, the colonoscopy follow-up rate decreased across all remoteness areas, although slight improvements were observed in Remote and Very Remote areas compared to 2016.^{1, 6}

Colorectal cancer control in Australia

Since the initial trial of national colorectal cancer screening through the pilot program and, subsequent implementation of the NBCSP, improvements have been observed in mortality and survival rates. The age-standardised colorectal cancer mortality rate has decreased from 24.7 deaths per 100,000 in 2002 to 18.7 per 100,000 in 2016 and the 5-year survival rate has increased from 62.9% in 2001–2005 to 69.9% in 2011–2015.^{1, 7} The AIHW has analysed outcomes for persons who, in the period 2006−2010, were: aged 50-74 years; and diagnosed with colorectal cancer. During this time, in Phases 1 and 2 of the NBSCP, invitations to screen were sent to persons turning 50, 55 or 65 years old. For persons who did not receive an invitation to screen, the risk of colorectal cancer death was 13% higher than for those that did receive an invitation to screen.⁸

The NCCI measures Capture of stage data and Distribution of cancer stage present national data for Registry-Derived stage (RD-Stage) at diagnosis for the top 5 cancers by incidence in 2011. These data show that people aged 50 years and over had a higher proportion of early stage colorectal cancers at diagnosis (stage 1 and stage 2) than those aged less than 50 years. RD-stage data collection in subsequent years will provide us with more detailed evidence regarding the impact of the NBSCP on early detection of colorectal cancer in the target age range.

About the data

This measure shows the proportion of the eligible invited population returning a positive (abnormal) result from a correctly completed FOBT screening test, who had a follow-up diagnostic assessment (colonoscopy).

Numerator: Number of persons who had a follow-up colonoscopy within 360 days.

Denominator: Number of persons who had a positive FOBT result in the defined 12-month period.

Remoteness

Participants were allocated to a remoteness area using the postcode supplied at the time of screening, using the Australian Statistical Geography Standard (ASGS) 2011.

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 for 2016.

Data sources

Australian Institute of Health and Welfare. AIHW Bowel cancer screening publications: Accessed December 2019; https://www.aihw.gov.au/reports-statistics/health-conditions-disability-deaths/cancer/reports

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.

Data caveats

The National Bowel Cancer Screening Program is being implemented in a phased approach. National screening of Australians aged 60-64 years did not commence until Phase 3 was implemented in 2013, and screening of 70-74 year olds commenced with the roll-out of Phase 4 in 2015 which incorporates biennial screening. ³

As reporting of colonoscopies to the NBCSP is not mandatory, there is an unknown degree of under-reporting that may affect the data. These data are based on information recorded in the Program Register only.

References

Activity in this area

Data:

Australian Institute of Health and Welfare. AIHW Bowel cancer screening publications: Accessed November 2019; https://www.aihw.gov.au/reports-statistics/health-conditions-disability-deaths/cancer/reports

Policy:

Australian Government Department of Health. National Bowel Cancer Screening Program Phase Four (2015-2020) Policy Framework. Accessed November 2019; http://www.cancerscreening.gov.au/internet/screening/publishing.nsf/Content/program-frameworks-and-strategies

References

1. Australian Institute of Health and Welfare 2019.National Bowel Cancer Screening Program: monitoring report 2019.Cat. no. CAN 125. Canberra: AIHW.

2. Australian Institute of Health and Welfare 2014.Analysis of bowel cancer outcomes for the National Bowel Cancer Screening Program. Canberra: AIHW.

3. Australian Government Department of Health 2017.National Bowel Cancer Screening Program Phase Four (2015-2020) Policy Framework.Version 0.8. Canberra: Australian Government Department of Health.

4. Australian Institute of Health and Welfare 2016.National Bowel Cancer Screening Program: monitoring report 2016.Cat. no. CAN 97. Canberra: AIHW.

5. Australian Institute of Health and Welfare 2017.National Bowel Cancer Screening Program: monitoring report 2017.Cat. no. CAN 103. Canberra: AIHW.

6. Australian Institute of Health and Welfare 2018.National Bowel Cancer Screening Program: monitoring report 2018.Cat. no. CAN 112. Canberra: AIHW.

7. Australian Institute of Health and Welfare 2019.Cancer in Australia 2019.Cat. no. CAN 123. Canberra: AIHW.

8. Australian Institute of Health and Welfare 2018.Analysis of bowel cancer outcomes for the National Bowel Cancer Screening Program 2018.Cat. no. CAN 113. Canberra: AIHW.

Summary

Almost two-thirds of people with a positive FOBT result had a follow-up colonoscopy recorded within 360 daysIn 2017, 66.1% of the eligible population with a positive FOBT result had a follow-up colonoscopy recorded within 360 days of this result.

The follow-up colonoscopy rate within 360 days was lower for Indigenous Australians than non-Indigenous Australians In 2017, 51.0% of Indigenous Australians with a positive FOBT result had a follow-up colonoscopy recorded within 360 days of this result, compared to 66.5% of non-Indigenous Australians.

The follow-up colonoscopy rate within 360 days was lower in areas that were Very Remote, and of lowest socioeconomic status In 2017, the follow-up rate was 53.0% in Very Remote areas compared to 70.3% in Major Cities, and 59.3% in the lowest SES areas (SES 1) compared to 74.2% for the highest SES areas (SES 5).

Revision Type

Minor

Version Number

1.2

National Cancer Control Indicators

Colonoscopy follow-up after a positive colorectal screening test

Data

Summary

Almost two-thirds of people with a positive FOBT result had a follow-up colonoscopy recorded within 360 days

The follow-up colonoscopy rate within 360 days was lower for Indigenous Australians than non-Indigenous Australians

The follow-up colonoscopy rate within 360 days was lower in areas that were Very Remote, and of lowest socioeconomic status

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Data

Summary

Almost two-thirds of people with a positive FOBT result had a follow-up colonoscopy recorded within 360 days

The follow-up colonoscopy rate within 360 days was lower for Indigenous Australians than non-Indigenous Australians

The follow-up colonoscopy rate within 360 days was lower in areas that were Very Remote, and of lowest socioeconomic status

Related features

Relative survival by stage at diagnosis 2011–2016, a snapshot in time

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