Performance indicator 5: Ductal carcinoma in situ (DCIS) detection
Summary
- 1,915 participants had DCIS detected through BreastScreen Australia in 2023, of whom 1,632 (85.2%) were aged 50–74.
- In 2023, the DCIS detection rate for participants aged 50–74 was higher in the first screening round at 26.2 per 10,000 participants screened than in subsequent screening rounds at 14.8 per 10,000 participants screened.
Definition
The number of participants aged 50–74 with DCIS detected through BreastScreen Australia per 10,000 participants screened.
Rationale
Women with DCIS are at an increased risk of later developing invasive breast cancer (AIHW 2010; IARC 2002). As it is not currently possible to predict which DCIS cases might progress to invasive breast cancer, they are treated similarly to invasive breast cancer. Further, given the increased risk of invasive breast cancer after a diagnosis of DCIS, and that the detection and subsequent treatment of high grade DCIS is likely to prevent deaths from invasive breast cancer, BreastScreen Australia aims to maximise the detection of DCIS, as for invasive breast cancer (BreastScreen Australia 2022).
Guide to interpretation
DCIS is disaggregated into first and subsequent screening rounds because a participant is more likely to have DCIS diagnosed at their first screen than subsequent screens, since their first visit detects prevalent cases, not just incident cases.
To produce stable, comparable rates from the relatively small number of DCIS cases, detection of DCIS is reported by 10-year age groups and, when disaggregated by state and territory, is presented for all screening rounds combined.
DCIS detection data are reported per 10,000 participants screened.
The most recent DCIS data are for participants screened in 2023.
More information on DCIS
DCIS is a non invasive tumour that arises from the lining of the ducts that carry milk from the milk producing lobules to the nipple. The changes to the cells lining the milk ducts seen in DCIS are similar to those in invasive breast cancer, but unlike invasive breast cancer, DCIS does not invade the surrounding breast tissue; instead, it is contained entirely within the milk duct.
Women with DCIS are at an increased risk of later developing invasive breast cancer (AIHW 2010; IARC 2002). BreastScreen Australia aims to maximise the detection of DCIS.
Results
In 2023, 1,632 participants aged 50–74 had DCIS detected through BreastScreen Australia. Of these, 301 were attending their first screen, equivalent to 26.2 participants diagnosed per 10,000 participants screened and 1,331 were attending a subsequent screen, equivalent to 14.8 participants diagnosed per 10,000.
DCIS detection trends
Between 2014 and 2023, the age-standardised DCIS detection rate for participants aged 50–74 for their first screening round varied between 23.9 and 30.3 participants with DCIS detected per 10,000 participants screened (Figure 5.1).
Over the same period the age-standardised DCIS detection rate for participants aged 50–74 for subsequent screening rounds varied between 11.6 and 14.8 per 10,000 participants screened (Figure 5.1).
Figure 5.1: DCIS detection, participants aged 50–74, first and subsequent screening rounds, 2014 to 2023
This line chart shows this varied between 23.9 and 30.3 for the first screening round and between 11.6 and 14.8 for subsequent screening rounds.
| Years | First screening round | Subsequent screening rounds |
|---|---|---|
| 2014 | 23.9 | 14.8 |
| 2015 | 25.2 | 12.8 |
| 2016 | 27.5 | 12.7 |
| 2017 | 28.5 | 11.6 |
| 2018 | 27.1 | 12.6 |
| 2019 | 25.5 | 11.8 |
| 2020 | 30.3 | 13.7 |
| 2021 | 23.9 | 13 |
| 2022 | 28.4 | 13.5 |
| 2023 | 27.5 | 13.8 |
Source: AIHW analysis of BreastScreen Australia data. Data for this figure are available in tables A5.1a and A5.1b.
DCIS detection by age
Similar to invasive breast cancer detection rates, DCIS detection rates increased with age.
In 2023, the DCIS detection rate for all screening rounds per 10,000 participants screened was 12.8 participants with DCIS detected through BreastScreen Australia for those aged 40–49, increasing to 23.9 for those aged 75 and over.
DCIS detection by state and territory
In 2023, the DCIS age-standardised detection rate for participants aged 50–74 for all screening rounds varied between the states and territories, from 9.5 to 19.2 per 10,000 participants screened.
AIHW (2010) Risk of invasive breast cancer in women diagnosed with ductal carcinoma in situ in Australia between 1995 and 2005, Cancer series number 51, catalogue number CAN 47, AIHW, Australian Government.
BreastScreen Australia 2022. National Accreditation Standards Commentary. Viewed 11 August 2023.
IARC (International Agency for Research on Cancer) 2002. IARC handbooks of cancer prevention. Volume 7: breast cancer screening. Lyon, France: IARC Press.