Published 29 Jun, 2021

Aboriginal and Torres Strait Islander people are more likely to be diagnosed with cancer that has progressed to an advanced stage.1,2

Stage at diagnosis indicates the extent to which a cancer has spread when first diagnosed. At an individual level, stage at diagnosis provides important information about prognosis. At a population level, stage at diagnosis provides contextual information for interpreting cancer survival, recurrence, and treatment patterns.

There is currently a lack of high-quality national information about stage at diagnosis for different cancers in Australia. Cancer Australia is working with population-based cancer registries and the Australasian Association of Cancer Registries (AACR) to develop nationally standardised methods for collecting these data. The Stage, Treatment and Recurrence (STaR) project has collected information about stage at diagnosis for the five most common cancers in Australia: breast cancer (in women), colorectal cancer, lung cancer, prostate cancer and melanoma. Through this project, information about stage at diagnosis among Aboriginal and Torres Strait Islander peoples is available for breast cancer (in women), colorectal cancer, lung cancer and prostate cancer.

In 2011, among Aboriginal and Torres Strait Islander people in Australia, two-thirds of breast cancer cases in women (66.4%) and the majority of prostate cancer cases (87.1%) were diagnosed at an early stage (stage 1 or 2). In contrast, half of colorectal cancer cases (50.9%) were diagnosed at a locally advanced or advanced stage (stage 3 or 4) and over half of lung cancer cases (59%) were diagnosed at a locally advanced or advanced stage (stage 3 or 4). The most common stage at diagnosis for lung cancer among Aboriginal and Torres Strait Islander people is stage 4 (45.8%).

More information about data sources, methods for collection, and guidance for interpreting the data can be found in the ‘About the Data’ tab.

Charts
  • Notes
    • Data are sourced from the Australian Institute of Health and Welfare. More information about data sources can be found in the ‘About the Data’ tab.
    • This analysis presents unadjusted crude proportions of cancer cases for which stage data are available.
    • Analyses are only available for New South Wales, Victoria, Queensland, Western Australia and Northern Territory, where higher completeness of reporting Indigenous status has been determined by the AIHW in past analyses.
    • Data for some stage categories that do not appear in the chart have been deliberately suppressed due to small numbers. Caution should be applied in interpreting these proportions, particularly for prostate cancer.
    Table caption
    Stage at diagnosis by cancer type and sex, 2011

This measure presents data about stage at diagnosis for the four most common cancers diagnosed in Aboriginal and Torres Strait Islander peoples in Australia. Data are sourced from New South Wales, Victoria, Queensland, Western Australia and the Northern Territory.

Data source

When a new case of cancer in Australia is diagnosed, it is reported to the cancer registry in the state or territory where the person lives. Notification of new cancer diagnoses to the cancer registry is required by law. National data, using data from each state and territory, is collated in the Australian Cancer Database (ACD), which is maintained by the Australian Institute of Health and Welfare (AIHW).3

Business rules have been developed to collect data on Registry-derived stage (RD-stage) at diagnosis for invasive cancers using data sources that are routinely accessible to all population-based cancer registries. To date, RD-Stage has been collected only for one index year (2011), as this represents the most up-to date cancer incidence data for which 5-year survival by stage could be reported in Australia. In collaboration with Cancer Australia, the population-based cancer registries and AACR, the AIHW has combined information on RD-Stage with information on cancer incidence from the ACD.

Data about stage of diagnosis of cancer among Aboriginal and Torres Strait Islander peoples in Australia relies on information being collected in cancer registries about whether a person diagnosed with cancer identifies as Aboriginal or Torres Strait Islander. While every registry collects information about Aboriginal and Torres Strait Islander status, the quality of this information varies. Currently, information about Aboriginal and Torres Strait Islander status from cancer registries in five states and territories is considered to be of a high enough quality for inclusion in national reports and analyses of cancer incidence: New South Wales, Victoria, Queensland, Western Australia and the Northern Territory.

Cancer types

Data about stage at diagnosis among Aboriginal and Torres Strait Islander peoples are available for breast cancer (in women), colorectal cancer, lung cancer and prostate cancer.

RD-Stage distribution for Aboriginal and Torres Strait Islander people in 2011

Due to the small number of incident cancer cases in a single year (2011), results of analysis by Indigenous status should be interpreted with caution. Data for some stage categories have been deliberately suppressed due to small numbers. Caution should be applied in interpreting these proportions, particularly for prostate cancer. Data are only available for cancer incidence data in this report for Aboriginal and Torres Strait Islander people in New South Wales, Victoria, Queensland, Western Australia and the Northern Territory, as these jurisdictions have a higher completeness of Indigenous status recording.

The distribution pattern of cancer stage at diagnosis for Aboriginal and Torres Strait Islander people varied by cancer type. Breast (female) and prostate cancer had a higher proportion of cases diagnosed as early stage (stage 1 or stage 2). Colorectal and lung cancer had higher proportions of locally advanced (stage 3) and metastatic cancers (stage 4). Specifically:

  • For female breast cancer, over half (66.4%) were diagnosed at an early stage (stage 1, 30.1%; stage 2, 36.3%). Slightly fewer cases were diagnosed as locally advanced (stage 3, 24.0%). Metastatic cancers (stage 4) represented 4.1% of cancers diagnosed.
  • For prostate cancer, almost all (87.1%) of incident cases were diagnosed at an early stage (stage1, 26.9%; stage 2, 60.2%). Locally advanced cancers (stage 3) represented 7.5% of incident cases.
  • For colorectal cancer, less than half (35.8%) were diagnosed at an early stage (stage 1, 15.1%; stage 2, 20.8%). Locally advanced cancers (stage 3) represented 31.1% of incident cases and metastatic cancers (stage 4) represented 19.8%.
  • For lung cancer, one in five cases (21.1%) were diagnosed at an early stage (stage 1, 11.1%; stage 2, 4.7%). Locally advanced cancers (stage 3) represented 13.2% of incident cases. Metastatic cancers represented the highest proportion (45.8%) of lung cancer cases.  

 

RD-stage distribution by sex in 2011 for Aboriginal and Torres Strait Islander people with cancer

The distribution of cancer stage at diagnosis for Aboriginal and Torres Strait Islander people varied by sex. For colorectal and lung cancers, females tended to have a lower proportion of stage 1 cancers and a higher proportion of stage 4 cancers compared to males.

  • For colorectal cancer, females tended to have lower proportions of stage 1 cancers than males (10.0% compared to 19.6%). A higher proportion of incident cases were diagnosed as metastatic (stage 4) cancers in females than males (26.0% compared to 14.3%).
  • For lung cancer, females tended to have lower proportions of stage 1 cancers than males (7.0% compared to 14.4%). A slightly higher proportion of incident cases were diagnosed as metastatic (stage 4) cancers in females than males (47.7% compared to 44.2%).

For a comparison of the RD-stage at diagnosis data to the broader Australian population, refer to Cancer Australia’s NCCI website.

Barriers and opportunities

Collection of data about cancer stage at diagnosis for Aboriginal and Torres Strait Islander peoples is important to:

  • understand how stage at diagnosis contributes to variations in survival (compared with other factors such as treatment)
  • identify the potential for further research and targeted cancer control strategies to support earlier diagnosis of cancer, especially in those cancers that are more commonly diagnosed at an advanced stage.

Detection of cancer at an earlier stage among Aboriginal and Torres Strait Islander peoples could be enhanced by increased awareness and knowledge among Aboriginal and Torres Strait Islander communities about cancer, its symptoms and survivability. For some Aboriginal and Torres Strait Islander people, co-morbidities may mask cancer symptoms. For others, mistrust of health services and fear of cancer may be a barrier to accessing advice and reporting symptoms. It is important that help-seeking is encouraged and supported through positive messaging. This includes encouraging participation in Australia’s three population-based cancer screening programs as well as strategies to improve the cultural safety of health services to encourage and help people to access advice and support.4

 

More information

Stage, Treatment and Recurrence (STaR) project

Aboriginal and Torres Strait Islander identification in national cancer data

Cancer screening

Optimal care pathway for Aboriginal and Torres Strait Islander people with cancer

National Aboriginal and Torres Strait Islander Cancer Framework

 

Unit of analysis:

The unadjusted crude proportion of cancer cases for which stage data are available for cases with a principal diagnosis of:

Cancer type* ICD-10-AM codes
Breast (female) C50
Colorectal C18.0, C18.2–C20
  • Colon

C18**
  • Rectal
 C19-C20
Lung C34
Melanoma*** C43
Prostate C61

*The top incident cancers that were eligible for staging comprise female breast cancer (ICD-10 code C50), colorectal cancer excluding appendix (C18.0, C18.2–C20), lung cancer excluding trachea (C34), and prostate cancer (C61). Certain morphology codes that were not eligible for staging are excluded, such as sarcomas, lymphomas or carcinoid tumours.

**Colon cancer (C18) excludes cancer of the appendix (C18.1)

 

Numerator: Incident cancer cases for a selected RD-Stage at diagnosis value (Capture of stage - staged or unknown, or Distribution of stage - stage 1, stage 2, stage 3, stage 4, or unknown) for a selected cancer type.

Denominator: All eligible RD-Stage records that were able to be matched to an incident cancer case in the ACD for the relevant cancer type. The denominator includes cases with an "Unknown" stage at diagnosis for which the registry did not have sufficient information to derive stage.

 

Scope:

RD-Stage

RD-Stage at diagnosis is defined as the best estimate of summary TNM stage of diagnosis as derived by cancer registries from data sources available to them. These data will be used for statistical purposes as opposed to clinical management and supporting individual patient care. Clinical requirements for prognostic precision differ from epidemiological requirements for comparability and statistical completeness.2 Specifically, the collection of RD-Stage:

  • Is intended for epidemiological population-based analyses only – in particular, this   information stage at diagnosis will assist in understanding the severity of disease across tumour types and different and sociodemographic groups as well as inform us of patterns of incidence and mortality.

The Business Rules have been tested and reviewed by all states and territories to ensure applicability across all Australian population based cancer registries. The Business Rules have also been endorsed as a national standard for the collection of stage data by the AACR.

 

Australian Cancer Database3

Cancer incidence indicates the number of new cancers diagnosed during a specified time period (usually one year). The major source of national cancer incidence data is the ACD which contains records of all primary, malignant cancers (except basal cell and squamous cell carcinomas of the skin) diagnosed in Australia since 1982.

All Australian states and territories have legislation that makes cancer a notifiable disease. Various designated bodies, i.e., institutions such as hospitals, pathology laboratories and registries of births, deaths and marriages, are required to report cancer cases and deaths to their jurisdictional cancer registries.

Each registry supplies incidence data annually to the AIHW under an agreement between the registries and the AIHW. These data are compiled into the ACD, the only repository of national cancer incidence data.

 

Linkage of RD-Stage and the ACD

The data used for reporting this measure have been created by linkage of data from RD-Stage collection and the ACD. These data are therefore limited to records that have been matched across these two collections. For this analysis, 3.7% records in the RD-Stage collection (approximately 2,500 out of 72,200 cases) have been excluded from these analyses for the following reasons:

  • RD-stage record did not link to the ACD.
  • The RD-Stage record linked to an ACD record that was out of scope.
  • RD-Stage record was ineligible for stage (such as sarcomas, lymphomas or carcinoid tumours)
  • RD-Stage record was a duplicate

A relatively small number of records (approximately 600, less than 1%) records in the ACD were in scope but did not link to the RD-Stage collection. These records did not link because:

  • They had been altered since being submitted to the ACD and were now out of scope; or
  • Had been staged at a point after diagnosis but not at diagnosis.

 

Data caveats

  • This analysis presents crude proportions that have not been adjusted.
  • Collection of these data has provided an insight into differences in the availability, extent and accessibility of information that is required to derive RD-Stage across Population-based Cancer Registries (PBCRs). Notably, the availability and quality of data accessible to PBCRs was found to improve during the study period.
  • Due to the small number of incident cancer cases in a single year (2011), results of analysis by Indigenous status should be interpreted with caution.
  • Analyses by Indigenous status are only available in this report for New South Wales, Victoria, Queensland, Western Australia and Northern Territory, where higher completeness of reporting Indigenous status has been determined by the AIHW in past analyses.

Activity in this area

Cancer Australia, 2008. A National Cancer Data Strategy for Australia. (https://canceraustralia.gov.au/sites/default/files/publications/ncds_final_web1_504af02093a68.pdf).

Cancer Australia. The Stage, Treatment, and Recurrence project. (https://canceraustralia.gov.au/research-data/cancer-data/improving-cancer-data).

Policy:

Cancer Australia. National Aboriginal and Torres Strait Islander Cancer Framework. 2015 Available from: https://canceraustralia.gov.au/publications-and-resources/cancer-australia-publications/overlay-context=affected-cancer/aboriginal-and-torres-strait-islander-people/national-aboriginal-and-torres-strait-islander-cancer-framework 

Cancer Australia. Optimal Care Pathway for Aboriginal and Torres Strait Islander people with cancer. 2018 Available from: https://canceraustralia.gov.au/publications-and-resources/cancer-australia-publications/optimal-care-pathway-aboriginal-and-torres-strait-islander-people-cancer 

 

Data:

Australian Institute of Health and Welfare: Australian Cancer Incidence and Mortality (ACIM) books provide incidence and mortality by cancer type and selected demographic groups. (https://www.aihw.gov.au/reports/cancer/acim-books/contents/acim-books).

Thursfield V, Farrugia H. Cancer in Victoria: Statistics & Trends 2014. Cancer Council Victoria, Melbourne 2015: Provides information on prostate cancer stage at diagnosis in Victoria.

http://www.cancervic.org.au/downloads/cec/cancer-in-vic/CCV-statistics-trends-2014.pdf

 

References

[1] Australian Institute of Health and Welfare & Cancer Australia 2013. Cancer in Aboriginal and Torres Strait Islander peoples of Australia: an overview. Cancer series no.78. Cat. no. CAN 75. Canberra: AIHW. https://www.aihw.gov.au/getmedia/aa938fd4-21e8-4854-9207-c70306e4f2b3/13732.pdf.aspx?inline=true [Accessed November 2020]

[2] Haigh M, Burns J, Potter C et al. Review of cancer among Aboriginal and Torres Strait Islander people. Australian Indigenous Health Bulletin 2018;18(3). http://healthbulletin.org.au/articles/review-of-cancer-2018/  [Accessed November 2020]

[3] Australian Institute of Health and Welfare Australian Cancer Database [Accessed November 2020]

[4] Cancer Australia, 2015. National Aboriginal and Torres Strait Islander Cancer Framework, Cancer Australia, Surry Hills, NSW. https://www.canceraustralia.gov.au/publications-and-resources/cancer-australia-publications/national-aboriginal-and-torres-strait-islander-cancer-framework [Accessed November 2020]

 

Summary

A high proportion of breast cancers and prostate cancers were diagnosed in Aboriginal and Torres Strait Islander people at an early stage

In 2011, the majority (66.4%) of female breast cancers were diagnosed as early stage (stage 1 and stage 2), and the majority (87.1%) of prostate cancers were diagnosed as early stage (stage 1 or stage 2).

A high proportion of colorectal cancers and lung cancers were diagnosed in Aboriginal and Torres Strait Islander peoples at an advanced stage

Colorectal cancers were most often diagnosed as locally advanced (31.1%). Lung cancers were most often diagnosed as advanced metastatic (45.8%).

The proportion of colorectal cancers and lung cancers diagnosed as metastatic tended to be higher for Aboriginal and Torres Strait Islander females compared to males

Among Aboriginal and Torres Strait Islander people with cancer, females tended to have higher proportions of metastatic (stage 4) cancers diagnosed (26.0% for colorectal and 47.7% for lung) compared to males (14.3% for colorectal and 44.2% for lung).

In this Measure