Quantifying the changes in survival inequality for Indigenous people diagnosed with cancer in Queensland, Australia

Utilising the CREATE quality appraisal tool to analyse Aboriginal and Torres Strait Islander peoples' involvement and reporting of cancer research in Australia

OBJECTIVE

We aimed to evaluate Aboriginal and Torres Strait Islander involvement in research focusing on cancer experiences using an Aboriginal and Torres Strait Islander quality appraisal tool (the QAT).

METHODS

We conducted a systematic review of the peer-reviewed literature on Aboriginal and Torres Strait Islander peoples' experiences associated with cancer, recently published elsewhere. We then appraised articles for the inclusion of Aboriginal and Torres Strait Islander-led research, community consultation, and involvement.

RESULTS

91 articles were appraised. A lack of Aboriginal and Torres Strait Islander-led research and consultation was reported in the majority of articles, only 10 (11%) demonstrated success across seven (50%) or more questions of the QAT.

CONCLUSIONS

This review underscores the need for anti-racist research and publication practices that actively engage Aboriginal and Torres Strait Islander peoples and researchers. This approach is vital to enhance cancer outcomes within these communities.

IMPLICATIONS FOR PUBLIC HEALTH

To advance and prioritise appropriate involvement of Aboriginal and Torres Strait Islander peoples in cancer research, the onus must be on 'systems owners,' including academic journals and institutions, to require and report genuine engagement as standard practice. Researchers will produce higher-calibre research with a strengths-based focus, advancing the cause of equitable research.

Systematic review of Aboriginal and Torres Strait Islander peoples' experiences and supportive care needs associated with cancer

BACKGROUND

Persistent disparities exist between Aboriginal and Torres Strait Islander peoples (the Indigenous peoples of Australia) and non-Indigenous Australians associated with cancer, with Aboriginal and Torres Strait Islander peoples experiencing a longer time to treatment, higher morbidity rates, and higher mortality rates. This systematic review aimed to investigate findings and recommendations in the literature about the experiences and supportive care needs of Aboriginal and Torres Strait Islander peoples with cancer in Australia.

METHODS

A qualitative systematic review was conducted using thematic analysis. Database searches were conducted in CINAHL, Informit, MEDLINE, ProQuest, Scopus, and Web of Science for articles published between January 2000 and December 2021. There were 91 included studies which were appraised using the Mixed Methods Appraisal Tool. The included studies reported on the experiences of cancer and supportive care needs in Aboriginal and Torres Strait Islander populations.

RESULTS

Six key themes were determined: Culture, family, and community; cancer outcomes; psychological distress; access to health care; cancer education and awareness; and lack of appropriate data. Culture was seen as a potential facilitator to achieving optimal cancer care, with included studies highlighting the need for culturally safe cancer services and the routine collection of Aboriginal and Torres Strait Islander status in healthcare settings.

CONCLUSION

Future work should capitalize on these findings by encouraging the integration of culture in healthcare settings to increase treatment completion and provide a positive experience for Aboriginal and Torres Strait Islander peoples with cancer.

A racial bias test with tertiary cancer centre employees: why anti-racist measures are required for First Nations Australians cancer care equity

Objective To examine implicit bias in employees at a cancer centre using an Australian race (Aboriginal-white) Implicit Association Test (IAT), in an attempt to understand a potential factor for inequitable outcomes of First Nations Australians cancer patients. Methods All employees at an Australian cancer centre were invited to take part in a web-based, cross-sectional study using an Australian race IAT. The results were analysed using Welch t-tests, linear regression and ANOVA. Results Overall, 538/2871 participants (19%) completed the IAT between January and June 2020. The mean IAT was 0.147 (s.d. 0.43, P < 0.001, 95% CI 0.11-0.18), and 60% had a preference for white over First Nations Australians. There was no significant mean difference in IAT scores between sub-groups of gender, age or clinical/non-clinical employees. 21% of employees (95% CI 17.65-24.53) had moderate to strong preference for white over First Nations Australians, compared to 7.1% with moderate to strong preference for First Nations over white Australians (95% CI 5.01-9.09). Conclusions Inequitable cancer survival for First Nations patients has been well established and cancer is now the leading cause of mortality. This paper documents the presence of racial bias in employees at one cancer centre. We argue that this cannot be understood outside the history of colonialism and its effects on First Nations Australians, healthcare workers and our society. Further research is required to evaluate measures of racism, its effect on health care, and how to eliminate it.

Cancer survival differentials for Aboriginal and Torres Strait Islander peoples in Queensland: the impact of remoteness

PURPOSE

In Australia, Aboriginal and Torres Strait Islander peoples (First Nations population) often have low overall cancer survival, as do all residents of geographically remote areas. This study aimed to quantify the survival disparity between First Nations and other Queenslanders for 12 common cancer types by remoteness areas.

METHODS

For all Queensland residents aged 20-89 years diagnosed with a primary invasive cancer during 1997-2016, we ran flexible parametric survival models incorporating age, First Nations status, sex, diagnosis time period, area-level socioeconomic status, remoteness categories and where appropriate, broad cancer type. Three survival measures were predicted: cause-specific survival, survival differences and the comparative survival ratio, each standardised to First Nations peoples' covariate distributions.

RESULTS

The standardised five-year cause-specific cancer survival was 60% for urban First Nations and 65% for other Queenslanders, while remote residents were 54% (First Nations) and 58% (other). The absolute survival differential between First Nations and other Queenslanders was often similar, regardless of remoteness of residence. The greatest absolute difference in five-year standardised cancer survival was for head and neck cancers, followed by cervical cancer. The five-year comparative survival ratio (First Nations: other Queenslanders) for urban cancer patients was 0.91 (95% CI 0.90-0.93), similar to outer regional, inner regional and remote areas. The greatest comparative survival differential was for oesophageal cancer.

CONCLUSION

First Nations' survival inequalities are largely independent of geographical remoteness. It remains a priority to determine the contribution of other potential factors such as the availability of culturally acceptable diagnostic, management and/or support services.

Factors associated with cancer survival disparities among Aboriginal and Torres Strait Islander peoples compared with other Australians: A systematic review

Background

While cancer survival among Aboriginal and Torres Strait Islander peoples has improved over time, they continue to experience poorer cancer survival than other Australians. Key drivers of these disparities are not well understood. This systematic review aimed to summarise existing evidence on Aboriginal and Torres Strait Islander cancer survival disparities and identify influential factors and potential solutions.

Methods

In accordance with PRISMA guidelines, multiple databases were systematically searched for English language peer-reviewed articles on cancer survival by Aboriginal and Torres Strait Islander status published from 1/1/2008 to 4/05/2022. Observational studies presenting adjusted survival measures in relation to potential causal factors for disparities were included. Articles were screened independently by two authors. Included studies were critically assessed using Joanna Briggs Institute tools.

Results

Thirty population-based and predominantly state-level studies were included. A consistent pattern of poorer unadjusted cancer survival for Aboriginal and Torres Strait Islander peoples was evident. Studies varied widely in the covariates adjusted for including a combination of socio-demographics, cancer stage, comorbidities, and treatment. Potential contributions of these factors varied by cancer type. For lung and female breast cancer, adjusting for treatment and comorbidities reduced the survival disparity, which, while still elevated was no longer statistically significant. This pattern was also evident for cervical cancer after adjustment for stage and treatment. However, most studies for all cancers combined, or colorectal cancer, reported that unexplained survival disparities remained after adjusting for various combinations of covariates.

Conclusions

While some of the poorer survival faced by Aboriginal and Torres Strait Islander cancer patients can be explained, substantial disparities likely to be related to Aboriginal determinants, remain. It is imperative that future research consider innovative study designs and strength-based approaches to better understand cancer survival for Aboriginal and Torres Strait Islander peoples and to inform evidence-based action.

Quantifying the number of deaths among Aboriginal and Torres Strait Islander cancer patients that could be avoided by removing survival inequalities, Australia 2005–2016

Background

While Aboriginal and Torres Strait Islander peoples have poorer cancer survival than other Australians, absolute measures of survival disparities are lacking. This study quantified crude probabilities of deaths from cancer and other causes and estimated the number of avoidable deaths for Aboriginal and Torres Strait Islanders if these survival disparities were removed.

Methods

Flexible parametric relative survival models were used to estimate reported measures for a population-based cohort of 709,239 Australians (12,830 Aboriginal and Torres Strait Islander peoples), 2005–2016.

Results

Among Aboriginal and Torres Strait Islander peoples, the 5-year crude probability of cancer death was 0.44, while it was 0.07 for other causes of death. These probabilities were 0.07 and 0.03 higher than among other Australians, respectively. Magnitude of these disparities varied by cancer type and ranged for cancer deaths from <0.05 for pancreatic, prostate and uterine cancers to 0.20 for cervical and head and neck cancers. Values for disparity in other causes of death were generally lower. Among an average cohort of Aboriginal and Torres Strait Islander peoples diagnosed per year over the most recent five-year diagnosis period (2012–2016, n = 1,269), approximately 133 deaths within 5 years of diagnosis were potentially avoidable if they had the same overall survival as other Australians, with 94 of these deaths due to cancer. The total number of avoided deaths over the entire study period (2005–2016) was 1,348, with 947 of these deaths due to cancer.

Conclusions

Study findings suggest the need to reduce the prevalence of risk factors prevalence, increase screening participation, and improve early detection, diagnosis and treatment rates to achieve more equitable outcomes for a range of cancer types. Reported measures provide unique insights into the impact of a cancer diagnosis among Aboriginal and Torres Strait Islander peoples from a different perspective to standard relative survival measures.

Quantifying Differences in Remaining Life Expectancy after Cancer Diagnosis, Aboriginal and Torres Strait Islanders, and Other Australians, 2005-2016

BACKGROUND

This study quantified differences in remaining life expectancy (RLE) among Aboriginal and Torres Strait Islander and other Australian patients with cancer. We assessed how much of this disparity was due to differences in cancer and noncancer mortality and calculated the population gain in life years for Aboriginal and Torres Strait Islanders cancer diagnoses if the cancer survival disparities were removed.

METHODS

Flexible parametric relative survival models were used to estimate RLE by Aboriginal and Torres Strait Islander status for a population-based cohort of 709,239 persons (12,830 Aboriginal and Torres Strait Islanders), 2005 to 2016.

RESULTS

For all cancers combined, the average disparity in RLE was 8.0 years between Aboriginal and Torres Strait Islanders (12.0 years) and other Australians (20.0 years). The magnitude of this disparity varied by cancer type, being >10 years for cervical cancer versus <2 years for lung and pancreatic cancers. For all cancers combined, around 26% of this disparity was due to differences in cancer mortality and 74% due to noncancer mortality. Among 1,342 Aboriginal and Torres Strait Islanders diagnosed with cancer in 2015 an estimated 2,818 life years would be gained if cancer survival disparities were removed.

CONCLUSIONS

A cancer diagnosis exacerbates the existing disparities in RLE among Aboriginal and Torres Strait Islanders. Addressing them will require consideration of both cancer-related factors and those contributing to noncancer mortality.

IMPACT

Reported survival-based measures provided additional insights into the overall impact of cancer over a lifetime horizon among Aboriginal and Torres Strait Islander peoples.

Emerging cancer incidence, mortality, hospitalisation and associated burden among Australian cancer patients, 1982 - 2014: an incidence-based approach in terms of trends, determinants and inequality

OBJECTIVE

Cancer is a leading killer worldwide, including Australia. Cancer diagnosis leads to a substantial burden on the individual, their family and society. The main aim of this study is to understand the trends, determinants and inequalities associated with cancer incidence, hospitalisation, mortality and its burden over the period 1982 to 2014 in Australia.

SETTINGS

The study was conducted in Australia.

STUDY DESIGN

An incidence-based study design was used.

METHODS

Data came from the publicly accessible Australian Institute of Health and Welfare database. This contained 2 784 148 registered cancer cases over the study period for all types of cancer. Erreygers' concentration index was used to examine the magnitude of socioeconomic inequality with regards to cancer outcomes. Furthermore, a generalised linear model was constructed to identify the influential factors on the overall burden of cancer.

RESULTS

The results showed that cancer incidence (annual average percentage change, AAPC=1.33%), hospitalisation (AAPC=1.27%), cancer-related mortality (AAPC=0.76%) and burden of cancer (AAPC=0.84%) all increased significantly over the period. The same-day (AAPC=1.35%) and overnight (AAPC=1.19%) hospitalisation rates also showed an increasing trend. Further, the ratio (least-most advantaged economic resources ratio, LMR of mortality (M) and LMR of incidence (I)) was especially high for cervix (M/I=1.802), prostate (M/I=1.514), melanoma (M/I=1.325), non-Hodgkin's lymphoma (M/I=1.325) and breast (M/I=1.318), suggesting that survival inequality was most pronounced for these cancers. Socioeconomically disadvantaged people were more likely to bear an increasing cancer burden in terms of incidence, mortality and death.

CONCLUSIONS

Significant differences in the burden of cancer persist across socioeconomic strata in Australia. Policymakers should therefore introduce appropriate cancer policies to provide universal cancer care, which could reduce this burden by ensuring curable and preventive cancer care services are made available to all people.

Measuring cancer in indigenous populations

It is estimated that there are 370 million indigenous peoples in 90 countries globally. Indigenous peoples generally face substantial disadvantage and poorer health status compared with nonindigenous peoples. Population-level cancer surveillance provides data to set priorities, inform policies, and monitor progress over time. Measuring the cancer burden of vulnerable subpopulations, particularly indigenous peoples, is problematic. There are a number of practical and methodological issues potentially resulting in substantial underestimation of cancer incidence and mortality rates, and biased survival rates, among indigenous peoples. This, in turn, may result in a deprioritization of cancer-related programs and policies among these populations. This commentary describes key issues relating to cancer surveillance among indigenous populations including 1) suboptimal identification of indigenous populations, 2) numerator-denominator bias, 3) problems with data linkage in survival analysis, and 4) statistical analytic considerations. We suggest solutions that can be implemented to strengthen the visibility of indigenous peoples around the world. These include acknowledgment of the central importance of full engagement of indigenous peoples with all data-related processes, encouraging the use of indigenous identifiers in national and regional data sets and mitigation and/or careful assessment of biases inherent in cancer surveillance methods for indigenous peoples.

Different survival analysis methods for measuring long-term outcomes of Indigenous and non-Indigenous Australian cancer patients in the presence and absence of competing risks

Background

Net survival is the most common measure of cancer prognosis and has been used to study differentials in cancer survival between ethnic or racial population subgroups. However, net survival ignores competing risks of deaths and so provides incomplete prognostic information for cancer patients, and when comparing survival between populations with different all-cause mortality. Another prognosis measure, “crude probability of death”, which takes competing risk of death into account, overcomes this limitation. Similar to net survival, it can be calculated using either life tables (using Cronin-Feuer method) or cause of death data (using Fine-Gray method). The aim of this study is two-fold: (1) to compare the multivariable results produced by different survival analysis methods; and (2) to compare the Cronin-Feuer with the Fine-Gray methods, in estimating the cancer and non-cancer death probability of both Indigenous and non-Indigenous cancer patients and the Indigenous cancer disparities.

Methods

Cancer survival was investigated for 9,595 people (18.5% Indigenous) diagnosed with cancer in the Northern Territory of Australia between 1991 and 2009. The Cox proportional hazard model along with Poisson and Fine-Gray regression were used in the multivariable analysis. The crude probabilities of cancer and non-cancer methods were estimated in two ways: first, using cause of death data with the Fine-Gray method, and second, using life tables with the Cronin-Feuer method.

Results

Multivariable regression using the relative survival, cause-specific survival, and competing risk analysis produced similar results. In the presence of competing risks, the Cronin-Feuer method produced similar results to Fine-Gray in the estimation of cancer death probability (higher Indigenous cancer death probabilities for all cancers) and non-cancer death probabilities (higher Indigenous non-cancer death probabilities for all cancers except lung cancer and head and neck cancers). Cronin-Feuer estimated much lower non-cancer death probabilities than Fine-Gray for non-Indigenous patients with head and neck cancers and lung cancers (both smoking-related cancers).

Conclusion

Despite the limitations of the Cronin-Feuer method, it is a reasonable alternative to the Fine-Gray method for assessing the Indigenous survival differential in the presence of competing risks when valid and reliable subgroup-specific life tables are available and cause of death data are unavailable or unreliable.

Electronic supplementary material

The online version of this article (doi:10.1186/s12963-016-0118-9) contains supplementary material, which is available to authorized users.