Cancer screening

Cervical cancer screening

Since the National Cervical Screening Program began in Australia in 1991, the number of women diagnosed with cervical cancer annually (incidence) and mortality have halved. Rates per 100,000 women declined from:

• 15.2 in 1991 to 7.9 in 2017 for cervical cancer incidence
• 4.3 in 1991 to 2.0 in 2019 for mortality.

The program and recommendations have undergone several changes as the evidence base improves.¹ When cervical cancer was linked to exposure to human papillomavirus (HPV), a more sensitive test using HPV DNA was developed. The increased test sensitivity meant that screening could start later and the time between tests (test interval) could be longer. In December 2017, program recommendations changed from a Pap smear every two years for women 20 to 69 years to a Cervical Screening Test (CST) based on HPV DNA every five years for women 25 to 74 years.¹

It will take five years to see how this change effects participation, but initial signs are encouraging. Four-year (2018–2021) interim participation estimates show that 62.1% (Queensland) and 62.4% (Australia) of women and people with a cervix had a CST.²

Australian results for 2018–2020 indicate areas for improvement such as:

• Women from the least disadvantaged area were 25% more likely to screen than women from the most disadvantaged.
• Women in major cities were 20% or more likely to screen than women from very remote areas.
• Although there were fewer CSTs in 2020, changes to the screening interval mean that COVID-19 effects cannot be assessed.

Introducing a more sensitive HPV test increased high-grade abnormality detection from 7.9 per 100,000 women in 2017 to 9.4 per 100,000 women in 2019—this is expected to be temporary.

As of 1 July 2022, participants can choose to self-collect their CST. This is also likely to lead to a temporary increase in high-grade abnormality detection as women at higher risk, such as people who have never screened, enter the program.

In the longer term, these changes should improve outcomes, with:

• a decrease in the incidence of high-grade abnormalities and cervical cancer as young people vaccinated against HPV continue to move into the CST target age and participate in cervical screening
• an overall decrease in mortality as cancers detected through screening have a 77% lower chance of causing death than cancers detected in people who have never screened.³

Breast cancer screening

Routine mammography screening every two years is the gold standard for population-based breast cancer screening across the world.⁴ The outcome for most women screened by BreastScreen Queensland is no signs of cancer, however:

• a small proportion (4.4% of women 50 to 74 years in 2021) of women were recalled for further investigation.
• of the women recalled around 1-in-7 is diagnosed with breast cancer (1,197 cancer diagnoses in 2021).

Cancer detection rates vary by screening history. Queensland rates for 2021 were:

• 101 per 10,000 screened for first time participants
• 55 per 10,000 screened for returning clients (second or subsequent screens).

In 2020, the national and Queensland cancer detection rates were similar.

Trends

Participation in the BreastScreen Queensland program has trended downwards in recent years. The COVID-19 pandemic made this worse and for 2020–2021, the age-standardised participation rate (ASRs or standardised rates) was 51.6% compared to 54.4% in 2018–2019.

COVID-19 impacts

BreastScreen services were suspended nationally in March 2020, recommenced in Queensland in late April, and were fully operational by 13 July 2020. Services compensated for this suspension with increased screens from July 2020 to the end of 2020 (6% above target). By the end of July 2021, the estimated number of missed screens had decreased by more than three-quarters for clients in the target age group.

Declines in standardised participation rates were also recorded for population subgroups and in different regions based on remoteness⁵ or socioeconomic status.⁶

From 2018–2019 to 2019–2020, participation rates for women 50 to 74 years decreased by (Figure 2):

• 1.8 percentage points (47.3% to 45.5%) for First Nations women
• 3.2 percentage points (53.4% to 50.2%) for culturally and linguistically diverse women
• about 3.5 percentage points in inner regional and very remote areas
• 3.1 percentage points in the most disadvantaged areas (51.5% to 47.6%).

Results for First Nations women and culturally and linguistically diverse women should be viewed with some caution due to difficulties determining the underlying population estimates.

It is increasingly recognised that risk-based, or individualised, approaches to breast screening could improve outcomes in Australia and internationally. This is made possible by new technologies, and increased evidence and a greater awareness of the range of personal, lifestyle and other risk factors associated with developing breast cancer. This information can be used to more accurately estimate a woman’s risk of breast cancer and to optimise screening intervals. This would mean:

• fewer screens over a lifetime for women at lower risk (and therefore fewer unnecessary follow up tests)
• potentially more screens over a lifetime for women at higher risk, leading to fewer interval cancers (those diagnosed between regular screenings) in this group.⁷

This approach is expected to improve population-based breast cancer screening and maximises the accuracy of screening tests.⁸ Further research in an Australian context is underway to find ways to improve the screening program in Australia. To implement a comprehensive risk-stratified breast screening program in the future, measuring and reporting of breast density—an important risk factor in breast cancer—is likely to be required.

Bowel cancer screening

The National Bowel Cancer Screening Program (NBCSP) began in 2006. The NBSCP is a non-invasive test that detects traces of blood in a stool sample, indicating the possible presence of bowel abnormalities that may be cancers or may lead to cancers. Once detected through screening, the pre-cursors to cancers can be removed and future cancers are prevented from developing. The program has since undergone a gradual expansion of:

• the eligible screening age for participants
• a reduction in the amount of time between screening episodes.

Since 2019, all eligible Australians 50 to 74 years receive a free bowel cancer screening kit in the mail every two years.

For program participants, a positive result means that further follow up test (usually a colonoscopy) is recommended. In 2019, the percentages of program participants who had positive screening test results were similar in Queensland (7.0%) and Australia (6.8%).

Of those with positive screening results:

• follow-up testing (colonoscopy) was higher in Queensland (72.2%) than it was nationally (62.0%).
• the percentage receiving a colonoscopy within the recommended 120 days was 61.9% in Queensland, compared with 53.5% nationally.

Participation

The 2020–2021 bowel cancer screening participation rate for Queenslanders (37.5%) was lower than the national rate of 40.9%. The gap between participation rates in Queensland and Australia has increased in recent years.

Sociodemographic differences

Bowel cancer screening participation rates increase with age and are higher for females than males. In Queensland in 2019–2020, the participation rates were (Figure 3):

• 27.9% for adults 50 to 54 years
• 50.4% for adults 70 to 74 years
• 39.4% for females and 35.6% for males in the 50 to 74 years age group (Figure 3).

Geographic differences and other factors contribute to lower screening participation. In Australia, people living in regional and rural areas tend to:⁹

• be diagnosed with bowel cancers at more advanced stages than those living in major cities
• have poorer 5-year survival rates
• have a more reactive approach to health care due to environmental or cultural factors which can result in lower participation in preventative health measures such as screening for early signs of cancer.

COVID-19 impacts on the bowel screening program were assessed but inconclusive.

Individual differences in attitudes and cognitive styles can also act as barriers to bowel cancer screening. The key challenge is determining effective ways to reduce morbidity and mortality and their implementation through policy and practice.¹⁰

An external review of the NBCSP in 2021 recommended the program shift from an expansion phase to an optimisation phase. Four opportunity areas were:¹¹

• increasing participation
• improving access to colonoscopy and reducing wait times
• improving data completeness
• promoting the program's research agenda.

Increasing access to testing kits may improve participation rates. This was trialled in First Nations health centres and has expanded to other sites such as general practices and local health centres.¹²

Additional information

Strategies and information

For information about cancer screening programs, please visit:

• BreastScreen Queensland
• Cancer screening on the Queensland Health website.

References

1. Cox B. & Sneyd M.J. 2018. HPV screening, invasive cervical cancer and screening policy in Australia. Journal of the American Society of Cytopathology. 7(6): 292–299. doi: 10.1016/j.jasc.2018.07.003.
2. Australian Institute of Health and Welfare. 2019. Cervical screening in Australia 2019. Cancer series no. 123. Cat. no. CAN 124. Canberra: AIHW.
3. Australian Institute of Health and Welfare. 2019. Analysis of Cervical Cancer and Abnormality Outcomes in an Era of Cervical Screening and HPV Vaccination in Australia. Canberra: AIHW.
4. Kou K., Cameron J., Aitken J.F., Youl P., Turrell G., Chambers S., Dunn J., Pyke C. & Baade P.D. 2020. Factors associated with being diagnosed with high severity of breast cancer: a population-based study in Queensland, Australia. Breast cancer research and treatment. 184(3): 937–950. doi: 10.1007/s10549-020-05905-x.
5. Hugo Centre for Population and Migration Studies. 2018. Accessibility/remoteness index of Australia (ARIA). Accessibility/Remoteness Index of Australia (ARIA). Accessed: 1 October 2022.
6. Australian Bureau of Statistics. 2018. Socio-Economic Indexes for Areas (SEIFA) 2016. 2033.0.55.001 - Census of Population and Housing: Socio-Economic Indexes for Areas (SEIFA), Australia, 2016. Accessed: 1 October 2022.
7. Cancer Council. 2022. Roadmap for Optimising Screening in Australia - Breast.
8. Protani M., Page A., Taylor R., Glazebrook R., Lahmann P.H., Branch E. & Muller J. 2012. Breast cancer risk factors in Queensland women attending population-based mammography screening. Maturitas. 71(3): 279–286. doi: 10.1016/j.maturitas.2011.12.008.
9. Goodwin B.C., March S., Ireland M., Crawford Williams F., Manksi D., Ford M. & Dunn J. 2019. Geographic variation in compliance with Australian colorectal cancer screening programs: the role of attitudinal and cognitive traits. Rural and remote health. 19(3): 4957. doi: 10.22605/RRH4957.
10. Feletto E., Lew J.-B., Worthington J., He E., Caruana M., Butler K., Hui H., Taylor N., Banks E., Barclay K., Broun K., Butt A., Carter R., Cuff J., Dessaix A., Ee H., Emery J., Frayling I.M., Grogan P., Holden C., Horn C., Jenkins M.A., Kench J.G., Laaksonen M.A., Leggett B., Mitchell G., Morris S., Parkinson B., St John D.J., Taoube L., Tucker K., Wakefield M.A., Ward R.L., Win A.K., Worthley D.L., Armstrong B.K., Macrae F.A. & Canfell K. 2020. Pathways to a cancer-free future: a protocol for modelled evaluations to minimise the future burden of colorectal cancer in Australia. BMJ open. 10(6): e036475. doi: 10.1136/bmjopen-2019-036475.
11. Deloitte Access Economics. 2021. Review of Phase Four of the National Bowel Cancer Screening Program. Deloitte.
12. Department of Health and Aged Care. 2022. Final Report on the National Indigenous Bowel Screening Pilot. Canberra: Australian Government.