Definition 

Number of persons aged 50-74 who completing a bowel screening test under the National Bowel Cancer Screening Program (NBCSP) in Victoria.  

Interpretation 

This indicator is a crude measure of persons who completed a bowel screening test in 2023. In contrast a calculated participation rate takes the total number of eligible persons invited in 2023 as the denominator and accounts for a range of other factors which may have precluded participation (e.g. out-migration).  

The number of persons screened in 2023 remained higher in females compared to males across all age groups.

The increased screening activity across Victoria in 2023 may be due to a number of factors, including National and State bowel screening campaigns and other screening activities delivered in 2023, including improved access to kits via the Alternative Access Model and NCSR, as well as the higher number of invitations issued in March quarter 2023 as indicated by the Australian Institute of Health and Welfare.  

Additionally, total screening volumes were closely aligned with LPHU population sizes, with larger populations (e.g. NEPHU and SEPHU) corresponding to higher screening volumes and smaller populations (e.g. Ovens-Murray and Goulburn Valley) associated with lower screening volumes. This trend was consistent for screening volumes and PHN population sizes.

Targeted interventions for specific age groups may assist in maintaining this encouraging increase in screening. 

Number of Persons Having a Bowel Cancer Screening Test in Victoria (Jan 2018 - Dec 2023)

1.  Definition

Number of persons aged 50-74 who had a bowel cancer screening test in Victoria from Jan 2018 to Dec 2023.

2.  Data sources

NCSR Raw Data Extract - released Nov 2024 - for period Jan 2018 - Dec 2023

3. Data items and Methodology

• Tables provide monthly or yearly count of persons returning a Bowel Screening Test and positivity rates within the timeframe (01/01/2018 - 31/12/2023). This is not a count of tests.
• The screening numbers encompass all iFOBT outcomes, including Positive, Negative, Inconclusive, and No test result. The positivity rate is determined by dividing the number of positive results by the total number of iFOBT results.
• Jurisdiction = Victoria (based on invitation sent)
• The state and postcode are determined by the address to which the most recent invitation to screen was sent prior to the report date for the participant's iFOBT kit.
• Where a participant has >1 screen, only the FIRST screen in the timeframe is included. For 2021, 2022 and 2023, the first screen in the calendar year is included. For 2018-2020, the first screen within the ad-hoc reporting service request timeframe is included, as listed in technical note 2 above.
• Age is calculated from the participant’s age at the invitation and the date of birth and is rounded down.
• Sex, not gender, is presented in this report. Sex is provided by Medicare.
• The report may include data from participants who are currently opted out of the NCSR if they have returned a kit before opt-out request being actioned.

4. There were known issues with the sending out of invitations following the transition of data from the National Bowel Cancer Screening Register to the National Cancer Screening Register in 2019, 2020 and 2021, resulting in delays and disruptions. This had a follow-on impact on the timing of screening by participants.        

5. Geocoding and validation of addresses were completed using the Experian Address Validation tool. The Australia Post Postal Address File was used as the reference dataset.

6. The Local Government Area (LGA) data in this report was derived using the following methods:

• For street addresses where the Experian Address Validation result indicated a high-quality match and Local Government Area (LGA) was populated by Experian, that LGA data is presented in this report.  
• For addresses which had a low-quality match, could not be matched, were PO Boxes or were missing LGA from Experian, and addresses prior to 2022, postcode was converted to LGA based on the following concordances:  

ASGS Geographic Correspondences Table 3 of file named CG_POSTCODE_2022_LGA_2022, which is a 2016 Mesh Block population weighted correspondence file.

Source: www.data.gov.au

Search for: ABS ASGS Correspondences

Click on: ASGS Geographic Correspondences (2021) Edition 3

Download: ASGS Edition 3 (2021) Correspondence Files (ZIP)

File name: CG_POSTCODE_2022_LGA_2022

Postcodes not listed in concordances were mapped manually to allow application of ABS concordances.

• Participants with Victorian postcodes mapped to LGAs outside Victoria were excluded from LGA and LPHU tables and therefore overall totals will not align with state totals.

7. To convert data from Local Government Area (LGA) to Local Public Health Unit (LPHU), we used the mapping document provided by DH.

8. During the COVID-19 pandemic, local public health units (LPHUs) were created to oversee local cases and outbreaks of COVID-19. As of July 2022, the nine LPHUs (three metropolitan and six regional) have expanded their roles to include disease prevention, population health, and the investigation and response to notifiable conditions. They are now tasked with managing local cases and outbreaks for more than 30 notifiable conditions.

• Metropolitan LPHUs: North Eastern Public Health Unit, South East Public Health Unit, Western Public Health Unit
• Regional LPHUs: Barwon South West, Goulburn Valley, Gippsland, Grampians, Ovens Murray, Loddon Mallee

9. The Primary Health Network (PHN) data in this report was derived using the following methods:

• For street addresses where the Experian Address Validation result indicated a high-quality match and longitude, and latitude were populated by Experian, longitude, and latitude were converted to Statistical Area 1 (SA1) based on the following ABS shapefile:

Source: https://www.abs.gov.au/statistics/standards/australian-statistical-geography-standard-asgs-edition-3/jul2021-jun2026/access-and-downloads/digital-boundary-files

Download: Statistical Areas Level 1 - 2021 - Shapefile

File name: SA1_2021_AUST_GDA2020.shp

SA1 was then converted to PHN based on the following concordances:

Primary Health Networks (PHN) (2023) – Statistical Area Level 1 (2021)

Source: www.data.gov.au

Search for: Primary Health Networks (PHN) concordance files

Click on: Primary Health Networks (PHN) concordance files

Download: Primary Health Networks (PHN) (2023) – Statistical Area Level 1 (2021)

• For addresses which had a low-quality match, could not be matched, were PO Boxes or were missing longitude and latitude from Experian, postcode was converted to PHN based on the following concordances:  

Primary Health Networks (PHN) (2023) – Postal Areas (2021)

Source: www.data.gov.au

Search for: Primary Health Networks (PHN) concordance files

Click on: Primary Health Networks (PHN) concordance files

Download: Primary Health Networks (PHN) (2023) – Postal Areas (2021)

Postcodes not listed in concordances were mapped manually to allow application of ABS concordances.

• Please note that due to rounding, overall total may not align with state totals.

10. Primary Health Networks (PHNs) are independent organisations that are funded by the Australian Government to oversee primary health care in their respective regions. PHNs evaluate the health needs of their communities and commission services to ensure that individuals can access coordinated care when and where it's needed. There are 6 Primary Health Network (PHN) regions in Victoria. 

• Metropolitan PHNs: Eastern Melbourne, North Western Melbourne, South Eastern Melbourne
• Regional PHNs: Gippsland, Murray, Western Victoria

11. Please note that the COVID-19 pandemic impacted screening services and health-seeking behaviours, which will be reflected in the data for 2020 - 2022.

12. The reduction in screens in the summer months may be attributed to the hot zone policy.

More information can be found here, The ‘hot zone policy’ for colorectal cancer screening presents unique risks and opportunities for rural Australia:

https://onlinelibrary.wiley.com/doi/10.1111/ajr.12977#:~:text=The%20hot%20zone%20policy%20means%20that%20National%20Bowel,months%20when%20the%20average%20temperature%20is%20over%2030%C2%B0C.

Definition:

Time to colonoscopy is the number of days between the date of the positive bowel screening test result and the date of the first subsequent colonoscopy. Reported as a percentage, calculated as follows.

• Numerator: Number of participants who returned a positive bowel screening test result and proceeded to colonoscopy as requested.
• Denominator: Total number of participants returning a positive bowel screening test result and being requested for a follow-up colonoscopy.

Colonoscopies performed within 4 months after a positive bowel screening test are considered timely as per clinical guidelines.

Interpretation

The proportion of participants attending for colonoscopy within 4 months of a positive screening test slightly increased overall, with 75.9% of participants attending within four months in 2023 compared with 73.2% in 2022. 

84% of participants overall attended for their recommended colonoscopy within 6 months in 2023.

The percentage of females attending for a colonoscopy in a timely manner (within 4 months of a positive screening test) has been consistently higher than males since 2018 which could partly be due to a higher likelihood among females to engage in health seeking behaviours. However, this gap appears to be narrowing over time from a 7% difference between females and males in 2018 to a 4% difference in 2023. 

Looking at the geographic stratification at Local Public Health Unit (LPHU) level, the proportion of participants attending a colonoscopy within 4 months of a positive screening test for the metropolitan LPHUs ranged from 72% to 79%, whilst the proportion for regional LPHUs ranged from 67% to 80%. 

Ongoing efforts are required at both the health systems and individual level to ensure that eligible participants have timely access to, and understand the importance of, colonoscopy for detection of bowel cancer at an earlier stage for improving health outcomes. 90% of bowel cancers can be treated successfully if detected early.  

Time to Colonoscopy (Jan 2018 - Dec 2023)

1. Definition:

Time to colonoscopy is the number of days between the date of positive iFOBT result and the first date of colonoscopy following the positive iFOBT test.

N (%) is calculated by:

• Numerator: Number of persons who returned a positive iFOBT result and proceeded to colonoscopy as requested.
• Denominator: Total number of persons returning a positive FOBT result and being requested for a follow-up colonoscopy.

2. Data sources:

NCSR Raw Data Extract (RDE) released Nov 2024 - for 2018 to 2023 data

3. This report includes colonoscopy procedures identified from the following tables in the NCSR RDE:

• Colonoscopy
• Histopathology
• Claims
• PFUF Colonoscopy follow up

4. The data presented in this report used episodes in the FOBT table with the Date Sample Reported, 01 Jan 2018 - 31 Dec 2023 and a FOBT Overall result = 1 (positive).

5. The period of screening 01 Dec 2018 - 31 Dec 2023 was split into six as follows:

• 2018 = FOBT with overall result = 1 from 01 Jan 2018 - 31 Dec 2018
• 2019 = FOBT with overall result = 1 from 01 Jan 2019 - 31 Dec 2019
• 2020 = FOBT with overall result = 1 from 01 Jan 2020 - 31 Dec 2020
• 2021 = FOBT with overall result = 1 from 01 Jan 2021 - 31 Dec 2021
• 2022 = FOBT with overall result = 1 from 01 Jan 2022 - 31 Dec 2022
• 2023 = FOBT with overall result = 1 from 01 Jan 2023 - 31 Dec 2023

6. Jurisdiction = Victoria (based on the postcode and state value at the time they reported an iFOBT sample)

Postcode is determined by the participants’ address at the time the iFOBT was completed. The address details are obtained from invitation letters sent to participants prior to the earliest test of each screening round.

7. Time to colonoscopy was calculated as the number of days between the date the first iFOBT sample within a screening round was reported to NCSR and the first date of colonoscopy.

To consider a colonoscopy as a valid colonoscopy, we looked at the colonoscopy dates that were on or after the date of iFOBT.

The following breakdowns were used:

• By 4 months
• By 6 months
• By 12 months
• Ever attended

8. The report includes data from participants who are currently opted out of the NCSR for the NBCSP, if their results were sent prior to the opt-out being actioned.

9. Age at the time of the episode was calculated as the number of years between the Date of Birth and the positive FOBT result and was restricted to ages 50-74 at the time of the positive FOBT.

10. Sex, not identified gender, is presented in this report. Sex is provided by Medicare.

11. Where a participant had one positive FOBT within a screening round but more than one subsequent colonoscopy within the full period of the report, only the first colonoscopy is included in the data.

For example, a participant who returned a single positive FOBT on 1-Jan-2019 and had a colonoscopy on 15-Jan-2019 and another colonoscopy in 2020, the participant would only be counted once in the data as <=30 days to colonoscopy in 2019.

12. If a person was referred to colonoscopy more than once within a screening round, we calculated time to colonoscopy from the first time they were referred.

We counted attendance depending on the scenarios below:

• Persons who returned multiple positive FOBT results but went to colonoscopy only once (same colonoscopy date for more than one positive FOBT date)

If a person returned a positive FOBT more than once but only had one colonoscopy, then the person was counted only once (first positive FOBT). Time to colonoscopy was calculated from the first time they returned a positive FOBT to the date of their only colonoscopy. All other times they were referred to colonoscopy were excluded from the data.

• Persons who have returned multiple positive FOBTs but have not attended to colonoscopy

If a person returned a positive FOBT more than once but has not had a colonoscopy, then the person was counted only once on the first time they returned a positive FOBT.

• Persons who have returned positive FOBT results more than once and went to colonoscopy after each positive result.

If a person returned a positive FOBT more than once and had more than one colonoscopy, then the person was counted every time they returned a positive FOBT, with the earliest colonoscopy on or after the date of positive FOBT.

13. Geocoding and validation of addresses was completed using the Experian Address Validation tool, using the Australia Post Postal Address File as the reference dataset.

14. The Local Government Area (LGA) data in this report was derived using the following methods:

• For street addresses where the Experian Address Validation result indicated a high-quality match and Local Government Area (LGA) was populated by Experian, that LGA data is presented in this report.  
• For addresses which had a low-quality match, could not be matched or were PO Boxes or were missing LGA from Experian, postcode was converted to LGA based on the following concordances:  

ASGS Geographic Correspondences Table 3 of file named CG_POSTCODE_2022_LGA_2022, which is a 2016 Mesh Block population weighted correspondence file.

Source: www.data.gov.au

Search for: ABS ASGS Correspondences

Click on: ASGS Geographic Correspondences (2021) Edition 3

Download: ASGS Edition 3 (2021) Correspondence Files (ZIP)

File name: CG_POSTCODE_2022_LGA_2022

Postcodes not listed in concordances were mapped manually to allow application of ABS concordances.

• Participants with Victorian postcodes mapped to LGAs outside Victoria were excluded from LGA and LPHU tables and therefore, overall totals will not align with state totals.

15. To convert data from Local Government Area (LGA) to Local Public Health Unit (LPHU), we used a mapping document provided by DH.

16. During the COVID-19 pandemic, local public health units (LPHUs) were created to oversee local cases and outbreaks of COVID-19. As of July 2022, the nine LPHUs (three metropolitan and six regional) have expanded their roles to include disease prevention, population health, and the investigation and response to notifiable conditions. They are now tasked with managing local cases and outbreaks for more than 30 notifiable conditions.

• Metropolitan LPHUs: North Eastern Public Health Unit, South East Public Health Unit, Western Public Health Unit
• Regional LPHUs: Barwon South West, Goulburn Valley, Gippsland, Grampians, Ovens Murray, Loddon Mallee

17. The Primary Health Network (PHN) data in this report was derived using the following methods:

• For street addresses where the Experian Address Validation result indicated a high-quality match and longitude, and latitude were populated by Experian, longitude, and latitude were converted to Statistical Area 1 (SA1) based on the following ABS shapefile:

Source: https://www.abs.gov.au/statistics/standards/australian-statistical-geography-standard-asgs-edition-3/jul2021-jun2026/access-and-downloads/digital-boundary-files

Download: Statistical Areas Level 1 - 2021 - Shapefile

File name: SA1_2021_AUST_GDA2020.shp

SA1 was then converted to PHN based on the following concordances:

Primary Health Networks (PHN) (2023) – Statistical Area Level 1 (2021)

Source: www.data.gov.au

Search for: Primary Health Networks (PHN) concordance files

Click on: Primary Health Networks (PHN) concordance files

Download: Primary Health Networks (PHN) (2023) – Statistical Area Level 1 (2021)

• For addresses which had a low-quality match, could not be matched, were PO Boxes or were missing longitude and latitude from Experian, postcode was converted to PHN based on the following concordances:  

Primary Health Networks (PHN) (2023) – Postal Areas (2021)

Source: www.data.gov.au

Search for: Primary Health Networks (PHN) concordance files

Click on: Primary Health Networks (PHN) concordance files

Download: Primary Health Networks (PHN) (2023) – Postal Areas (2021)

Postcodes not listed in concordances were mapped manually to allow application of ABS concordances.

Please note that due to rounding, overall total may not align with state totals.

18. Primary Health Networks (PHNs) are independent organisations that are funded by the Australian Government to oversee primary health care in their respective regions. PHNs evaluate the health needs of their communities and commission services to ensure that individuals can access coordinated care when and where it's needed. There are 6 Primary Health Network (PHN) regions in Victoria. 

• Metropolitan PHNs: Eastern Melbourne, North Western Melbourne, South Eastern Melbourne
• Regional PHNs: Gippsland, Murray, Western Victoria

19. Please note that the COVID-19 pandemic impacted screening services and health seeking behaviours which will be reflected in the data in 2020-2022.