Disease Outcome Indicators

Cervical cancer incidence is the measure used by the WHO to determine whether elimination has been achieved (1).

In 2019, 945 women were diagnosed with cervical cancer in Australia, an incidence rate of 6.4 per 100,000. Incidence varied between groups and rates (over the period 2015-2019) were three times as high as the elimination target in Indigenous women, and at least twice as high as the elimination target in women living in Tasmania or very remote areas (Figure 1.1). There is a socioeconomic gradient in cervical cancer incidence, with the incidence rates becoming higher with increasing levels of socioeconomic disadvantage. In Indigenous women, a 68% reduction is required to reach the elimination target.

In most demographic groups, cervical cancer incidence rates in 2015-2019 were broadly similar to those in recent preceding 5-year periods, although in some groups there was an apparent increase (Aboriginal and Torres Strait Islanders, Tasmania). Conversely, rates appear to have decreased over multiple recent time periods in some groups (people living in the two least socioeconomically disadvantaged quintiles, WA).

Cervical cancer rates were similar in 2019 to those in 2018 (6.4 per 100,000, compared to 6.5 per 100,000 in 2018) (Figure 1.2). This is consistent with an expected transient increase in cancer diagnoses that was expected to occur in 2018 as a result of Australia transitioning from 2-yearly cytology-based screening to 5-yearly primary HPV screening on 1st December 2017 (2).

The impact of HPV vaccination on cervical cancer incidence would be expected to occur gradually over time and affect younger age groups first. Cervical cancer incidence rates are extremely low in women aged less than 25, and the number of cases in women aged less than 25 is also very small (7 cases in 2019), making rates in these age groups unstable and difficult to interpret. Cervical cancer incidence has decreased over recent years in women aged 25-29 years (Figure 1.3).

Source: AIHW Australian Cancer Database, published in AIHW 2023 (3).

In many population groups, very few cases occur in a year, and so rates are subject to random fluctuation. For this reason, in order to report on and compare cancer incidence across a range of population groups, data are reported across a 5-year period. Results by Indigenous status are based on six jurisdictions (NSW, Vic, Qld, WA, ACT and NT) where data quality was considered sufficient for analysis. Cervical cancer incidence reported here is based on age-specific rates published in AIHW reports (3). Age-standardised rates are lower than in the AIHW reports, because the age-standardising method and standard population recommended by WHO for measuring cervical cancer elimination has been used (World 2015 female population), to enable comparison with the WHO target and internationally (1,4). In some jurisdictions, age-specific rates were not published for some age groups when they were non-zero and based on a cell size that was less than five, and there was additional suppression of adjacent cells. This affected every state except NSW and Victoria, except in 2015-2019 when full age-specific rates were also available for WA.  In 2015-2019, cases (and therefore age-specific rates) could be imputed from the remaining available data, but this was not possible for 2014-2018. In earlier 5-year periods, when there was not adjacent cell suppression, rates for Qld, WA, Tas, ACT and NT were based on imputed cases, or if necessary an assumption there were 2.5 cases, in some age groups. In addition to this, rates for the ACT and NT are based on fewer than 100 cases over a 5-year period. Trends for these jurisdictions should therefore be interpreted with particular caution.

There is currently a delay of around five years in the availability of national cancer incidence data stratified by population groups in Australia, which limits our ability to conduct timely reporting of cervical cancer incidence in Australia against the primary WHO elimination target. In the context of this delay and reporting across a 5-year period (the period reported on here is 7-12 years after the vaccination program commenced), it is not surprising that cervical cancer rates in most population groups have not reduced substantially compared to the previous report.  More generally, it will take some time for all ages rates to be impacted by HPV vaccination, due to the long time between a vaccine delivered in early adolescence, a prevented HPV infection and the cancer which otherwise would have occurred. The period reported on (2015-2019) also straddles the change to the screening program, when there was expected to be a transient increase in detection of cancer, due to the more sensitive test detecting some prevalent cancers (noting this represents a success of the new program since earlier detection leads to downstaging of cancer and improved survival). In spite of these limitations, cervical cancer rates in those aged 25-29 years appear to have declined in recent years (although based on fewer than 60 cases in each year over 2015-2019).

In the current report, results could not be calculated for every state and territory, as age-specific incidence rates were not published (and could not be inferred from other published numbers). This affects results in 2015-2019 for every state and territory, with the exception of NSW, Victoria and WA.

1 World Health Organization. Global strategy to accelerate the elimination of cervical cancer as a public health problem. 2020. Available at: https://www.who.int/ publications/i/item/9789240014107.

2 Hall MT, Simms KT, Lew JB, et al. Projected future impact of HPV vaccination and primary HPV screening on cervical cancer rates from 2017-2035: Example from Australia. PLoS One 2018; 13(2): e0185332.

3 Australian Institute of Health and Welfare. National Cervical Screening Program monitoring report 2023. Cat. no: CAN 157 Canberra: Australian Government.

4 Canfell K, Kim JJ, Brisson M, et al. Mortality impact of achieving WHO cervical cancer elimination targets: a comparative modelling analysis in 78 low-income and lower-middle-income countries. Lancet 2020; 395(10224): 591-603.

Reducing premature mortality from cervical cancer is the overarching aim of the WHO elimination strategy, so cervical cancer mortality has been identified as a key impact indicator in the global strategy to accelerate elimination (1). Cervical cancer mortality will capture two things that will not be reflected in cervical cancer incidence rates: downstaging (due to screening) and the WHO target of treating 90% of women diagnosed with cervical cancer.

In 2021, there were 229 deaths from cervical cancer. Cervical cancer mortality was 1.3 per 100,000 women in 2017-2021 with some variation in mortality across the population, most notably higher rates for Aboriginal and Torres Strait Islander women and women living in very remote areas, and a socioeconomic gradient (Figure 2.1).

Source: AIHW Australian Cancer Database, published in AIHW 2023 (2).

In order to report on cancer mortality across a range of population groups, data are reported across a 5-year period (the most recent 5-year period for which data are available). Age-specific rates were sourced from the most recent national report (2). Age-standardisation is performed across all ages using the 2015 World female population, consistent with the methodology recommended for incidence as part of the WHO elimination strategy (1). As a result of this difference in methodology, mortality rates in this report are not comparable to AIHW reports.

National mortality data are more timely than national cancer incidence data. Cervical cancer mortality is relatively low in many groups but many of the groups with higher rates correspond with those with a higher incidence (higher rates in Aboriginal and Torres Strait Islander women and increasing rates with increasing level of socioeconomic disadvantage). There is considerable overlap in the groups identified as having the highest mortality rates (Aboriginal and Torres Strait Islander women and women living in very remote areas). 

Reductions in cervical cancer mortality over time will reflect a range of factors, including improved prevention, earlier detection (downstaging), improvements to treatment, and providing more women with optimal treatment.

1 World Health Organization. Global strategy to accelerate the elimination of cervical cancer as a public health problem. 2020. Available at: https://www.who.int/ publications/i/item/9789240014107.

2 Australian Institute of Health and Welfare. National Cervical Screening Program monitoring report 2023. Cat. no: CAN 157 Canberra: Australian Government.

Cervical screening aims to detect specific types of cervical disease (known as high-grade -see Methods tab for details), that are considered to be the precursors of cervical cancer, so that women can have treatment to prevent progression to cancer. High-grade abnormalities of the cervix include cervical intraepithelial neoplasia (CIN) that has been graded as moderate (CIN 2) or severe (CIN 3), or for which the grade has not been specified, as well as endocervical dysplasia and adenocarcinoma in situ (1).

This indicator measures the proportion of women screened who are found to have high-grade disease as defined by a positive result on biopsy/histopathology. It will be determined by the underlying proportion with high-grade disease in the screened population, the accuracy of the screening method used, and the subsequent diagnostic steps and follow up undertaken with women found positive on the screening method.

Nationally, detection of high-grade cervical disease in 2021 was 16.3 per 1,000 screened women aged 25-74 years (age adjusted rate 14.8 per 1,000) (Figure 3.1). The rate of CIN3 detection was 9.5 per 1,000 (age adjusted 8.6 per 1,000 and 58.0% of all high-grade disease detected). AIS was detected at a rate of 0.6 per 1,000 (3.9% of all high-grade disease) (Figure 3.2). Women residing in the least socioeconomically disadvantaged quintile had a high-grade detection rate lower than the national average (14.8 per 1,000). The rate of high-grade detection increased with increasing remoteness of residence, exceeding 20 per 1000 women in very remote areas (21.3 per 1000). Queensland had the highest detection rate at 19.8 per 1,000 screened women (Figure 3.1).

Detection of high-grade cervical disease, and of CIN3 and AIS was highest in the 30–34-year-old age group at 24.4 and 14.6 and 1.1 per 1,000 screened women respectively (Figure 3.2). Detection of AIS was highest at aged 35–­39 years (1.1 per 1,000). The age group with the highest proportion of high-grade disease that was CIN3 was the 65-69-year-old age group (63.2%) and the lowest proportion was those aged 25-29 at 53.4%. The age group with the highest proportion of high-grade disease that was AIS was the 35-34-year-old age group (at 4.5%).

High-grade detection rates by Indigenous status were unavailable for publication.

Source: Analysis of NCSR data (NCSR RDE 14/01/2023); data prepared by the Screening Analysis and Monitoring Unit of the Australian Institute of Health and Welfare.

High-grade cervical disease was defined as a histology result of S3.1 (High-grade intraepithelial lesion (HSIL) (CIN NOS)), S3.2 (HSIL (CIN 2)), S3.3 (HSIL (CIN 3)) or E3.1 (Endocervical dysplasia), E3.2 (Adenocarcinoma in situ) or E3.3 (Mixed carcinoma in situ/adenocarcinoma in situ) (2).

Crude rates are presented, except for the national high grade and CIN3 rate, due to the suppression of small cell sizes preventing calculation of age standardised rates. Cell suppression impacted some age groups for AIS and for stratifications by State and Territory, remoteness and socioeconomic status. Age-standardised rates were the number of women with a high-grade abnormality detected by histology per 1,000 women screened, age-standardised to the Australian 2001 Standard Population (3).

In the final six months of the previous Pap based screening program (Jan-July 2017), the crude high grade detection rate for women aged 25-74 years was 6.6 per 1,000 screened women and highest in the 25–29-year-old age group (at 14.4 per 1,000) (4). As observed in 2020, the 2021 rate was significantly higher, as was predicted by modelling (5), both due to the move to HPV based screening with its higher sensitivity and because women attending were all at relatively higher risk of high-grade disease: women screening in 2021 were either entering the program at age 25, were attending because they were under surveillance for a previous positive HPV test, or else were overdue for screening (due to the transition from the previous 2nd yearly screening interval). The peak rate occurred in women aged 30-34, likely due to significant vaccine impact preventing disease in 25–29-year-old women (who would have been offered HPV vaccine in 2007 at age 12-16, prior to the average age of sexual debut in Australia). Women offered HPV vaccination as catch up as adults (aged 18-26 in 2007) were aged 32 to 40 in 2021.

There is known under-enumeration of histopathology reports held in the NCSR, as safety net follow-up (and attempts to retrieve not yet notified histopathology) cease when an MBS item number consistent with cervical histology is located (indicating the woman has received further assessment). Additionally, due to teething issues during initial register implementation, 2018 data is known to be incomplete. It is likely that high grade rates estimated from the early years (2018-2019, age standardised high grade rate of 8.0 and 9.4 per 1000, peaking at age 25-29 years (6)) may more significantly underestimate the true high-grade detection rate, with reporting to the register improving over time, so these data should be interpreted with caution. 

There was evidence of variation in high grade detection rate by remoteness of residence, with women in remote areas having higher rates, and by socioeconomic quintile of residence, with women living in the least disadvantaged quintile having lower rates. Women residing in Queensland, Tasmania and WA had higher rates than in other jurisdictions in 2021. National data by Indigenous status remain unavailable for inclusion in this report, although the AIHW published some data for the first time in December 2023 (6). HPV positivity rates were higher amongst Aboriginal and Torres Strait Islander participants aged 25-74 years (13.9%) than observed for the overall 2022 participant cohort (10.3%) (6). 

1 Australian Institute of Health and Welfare. National Cervical Screening Program monitoring report 2021. Cancer Series 134. Cat. no: CAN 141 Canberra: AIHW; 2021.

2 Australian Institute of Health and Welfare. National Cervical Screening Program data dictionary: version 1.1. Catalogue number CAN 146 Canberra: AIHW; 2022.

3 Australian Bureau of Statistics. Australia 2001 Standard Population for Use in Age-Standardisation. 2003. Available at: https://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/3101.0Mar%202013?OpenDocument

4 Australian Institute of Health and Welfare 2019. Cervical screening in Australia 2019. Cancer series no. 123. Cat. no. CAN 124. Canberra: AIHW

5 Hall MT, Simms KT, Lew JB, et al. Projected future impact of HPV vaccination and primary HPV screening on cervical cancer rates from 2017-2035: Example from Australia. PLoS One 2018; 13(2): e0185332.

6 Australian Institute of Health and Welfare (2023) National Cervical Screening Program monitoring report 2023, catalogue number CAN 157, AIHW, Australian Government.

The ability to achieve cervical cancer elimination is dependent upon the reduction in the prevalence of oncogenic HPV types through HPV vaccination. Monitoring infection prevalence in settings where this is feasible provides a direct measure of the extent to which this reduction is achieved and maintained over time.

In 2022, 1.9% of women screened aged 25-74 years were positive for HPV16 or 18, the most oncogenic HPV types prevented by vaccines utilised in the National HPV Vaccination Program. Positivity was slightly higher for Indigenous women compared with non-Indigenous populations (2.5% versus 1.8%). Minimal variations were observed across socioeconomic quintiles, remoteness areas, and States and Territories (Figure 4.1).

Overall positivity for oncogenic HPV types was 10.3%, with higher positivity apparent for Indigenous women (13.9%), women living in very remote areas (12.8%), and women in the NT (13.2%). The positivity for oncogenic HPV was influenced by types other than HPV16 or 18 (Figure 4.1).

HPV16 or 18 positivity was marginally lower in 2022 than in previous years (2018 through 2021). This pattern was evident in socioeconomic quintiles, remote areas, and most states and territories. In a breakdown by age groups, 2022 positivity was lowest at 1.1% for women aged 25–29, decreasing from 2.0% in 2018. Positivity was also lower at 30–34 years in 2022 for the first time, compared with previous years. For older age groups, positivity was relatively stable over time (Figure 4.2a).

Positivity for oncogenic HPV types overall and oncogenic types other than HPV16 or 18 was higher in 2022 than in 2019 and 2018 but similar to that of 2020 and 2021. This likely reflects that those screening in years 3-5 of the new 5 year interval were either young women entering screening or women who were by definition overdue for screening (under or never screened) following the transition from the previous 2 year interval. Across all years, positivity was similar across socioeconomic groups, but the highest positivity was evident for women living in very remote areas and the NT. In the breakdown by age groups, positivity was highest among women aged 25–29 years and decreased with increasing age. This pattern was consistent within and between years (Figure 4.2b and Figure 4.2c).

In 2022, positivity for the additional five HPV types targeted by the nonavalent HPV vaccine (HPV31, 33, 45, 52 or 58) and the remaining HPV types not targeted by vaccination (HPV35, 39, 51, 56, 59, 66 or 68) was 3.1% and 5.0% respectively, with little variation over time. Positivity was generally highest for women aged 25-29 and decreased with increasing age (Figure 4.3 and Figure 4.4).

Source: Analysis of NCSR data (NCSR RDE 14/1/2023); data prepared by the Screening Analysis and Monitoring Unit of the Australian Institute of Health and Welfare.

Results were derived using the standard method for calculating population prevalence (positivity): the sum of women with at least one positive result for a given HPV group divided by the total count of participants with a primary screening HPV test.

Calculations for Figure 4.1 and Figure 4.2 were based on all data reported to the NCSR. Figure 4.3 and Figure 4.4 were derived from a small subset of women whose samples were tested on two assays, which provided discrimination between non-16/18 oncogenic HPV types. This subset represents only 1% of all screening tests conducted in the program. Compared with national data for 2022, this group had slightly lower positivity for HPV16 and 18 (1.4% vs 1.9%) and oncogenic HPV types other than HPV16 or 18 (7.4% vs 8.8%).

Nationally, HPV prevalence in 2022 was stable compared with 2020-21. The age-specific patterns for HPV16 or 18 reflect the population-level impact of Australia’s quadrivalent HPV vaccination program on reducing infection with those types (1,2). Many HPV-vaccinated women have now attained the age at which they are participating in cervical screening, and vaccine coverage in schools has been increasing gradually over time. Women offered HPV vaccines in the catch-up program are turning 43 in the second half of 2023, and those in the school-based program are turning 33 to 34 years. The impact of the nonavalent vaccine is not apparent because these cohorts are not yet at screening age. The linkage between the NCSR and AIR will, in the future, permit comparisons of the prevalence of HPV infection detected at screening between vaccinated and unvaccinated women.

Available data by Indigenous status suggests a higher prevalence of oncogenic HPV among Indigenous compared with non-Indigenous women. However, the comparison of crude positivity should be interpreted with caution as they do not control for other factors that may impact positivity. These include age-specific differences in participation rates in cervical screening or differences in risk factors such as smoking (3). Surveys before the start of the vaccination program among women attending cervical screening suggested similar prevalence of HPV16/18 in Indigenous compared with non-Indigenous women at all ages, but a higher prevalence of other oncogenic types among Indigenous women aged 31 to 40 years (4). A survey conducted after the program had begun found declines in prevalence similar to those observed in non-Indigenous women, with an HPV16/18 prevalence among Indigenous women aged 18–26 of 1.4% in 2014-15 (5). A study of women aged 18-35 years recruited in 2015–2018 found that the prevalence of HPV16/18 was very similar in Indigenous and non-Indigenous women (2.3% versus 1.9%, respectively) (6). These findings are supported by national monitoring data, which showed that in 2022, HPV16 and 18 positivity was very low among Indigenous participants in birth cohorts offered HPV vaccination and similar to their non-Indigenous peers (1.8% versus 1.5%, respectively) (7).   

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7. Australian Institute of Health and Welfare (2023) National Cervical Screening Program monitoring report 2023, catalogue number CAN 157, AIHW, Australian Government.