Geographical and spatial disparities in the incidence and survival of rare cancers in Australia.

Rare cancers collectively account for around a quarter of cancer diagnoses and deaths. However, epidemiological studies are sparse. We describe spatial and geographical patterns in incidence and survival of rare cancers across Australia using a population-based cancer registry cohort of rare cancer cases diagnosed among Australians aged at least 15 years, 2007 to 2016. Rare cancers were defined using site- and histology-based categories from the European RARECARE study, as individual cancer types having crude annual incidence rates of less than 6/100 000. Incidence and survival patterns were modelled with generalised linear and Bayesian spatial Leroux models. Spatial heterogeneity was tested using the maximised excess events test. Rare cancers (n = 268 070) collectively comprised 22% of all invasive cancer diagnoses and accounted for 27% of all cancer-related deaths in Australia, 2007 to 2016 with an overall 5-year relative survival of around 53%. Males and those living in more remote or more disadvantaged areas had higher incidence but lower survival. There was substantial evidence for spatial variation in both incidence and survival for rare cancers between small geographical areas across Australia, with similar patterns so that those areas with higher incidence tended to have lower survival. Rare cancers are a substantial health burden in Australia. Our study has highlighted the need to better understand the higher burden of these cancers in rural and disadvantaged regions where the logistical challenges in their diagnosis, treatment and support are magnified.

Quantifying the absolute number of cancer deaths that would be avoided if cancers were diagnosed prior to progressing to distant metastasis, New South Wales, Australia 1985-2014.

Our study measures the impact of diagnosing cancers early before they metastasise on reducing the burden of cancer death. A cohort of 716 501 people aged 15 to 89 years diagnosed with a solid cancer in New South Wales, Australia, during 1985 to 2014 were followed-up to December 2015. Crude probabilities of cancer death by stage at diagnosis were calculated for all solid cancers combined and five individual cancers using flexible parametric relative survival models. These probabilities were used to estimate the number of avoided cancer deaths within 10 years of diagnosis in three 10-year diagnostic periods if all cases with known distant stage were instead diagnosed at an earlier stage. Cancers are known to be diagnosed at distant stage composed ~16% of all solid cancers diagnosed during 2005 to 2014. Assuming all these cases were instead diagnosed at regional stage, an annual average of 2064 cancer deaths would have been potentially avoided within 10 years of diagnosis. This equated to ~21% of modelled observed deaths. Alternatively, if half of all known distant cases diagnosed during 2005 to 2014 were diagnosed as regional and half as localised, the average number of deaths avoided per year would increase to 2677 (~28%). Estimates varied by diagnostic period, sex and cancer type, reflecting both the different stage distributions for the cancer types, and the respective survival differences between cancer stages. While prevention is the most effective pillar of cancer control, these findings quantify the potential benefits of diagnosing all cancer types when they are less advanced to reduce the burden of cancer mortality.

Global trends in incidence rates of childhood liver cancers: A systematic review and meta-analysis.

BACKGROUND: Childhood liver cancers are relatively rare, hence inferences on incidence trends over time are limited by lack of precision in most studies. OBJECTIVE: To conduct a systematic review and meta-analysis of published contemporary trends on childhood liver cancer incidence rates worldwide. DATA SOURCES: PubMed, EMBASE, CINAHL, Web of Science. STUDY SELECTION AND DATA EXTRACTION: English-language peer-reviewed articles published from 1 January 2008 to 1 December 2019 that presented quantitative estimates of incidence trends for childhood liver cancer and diagnostic subgroups. Review was conducted per PRISMA guidelines. Two authors independently extracted data and critically assessed studies. SYNTHESIS: Random effects meta-analysis models were used to estimate pooled incidence trends by diagnostic subgroups. Heterogeneity was measured using the Q and I2 statistics and publication bias evaluated using Egger's test. RESULTS: Eighteen studies were included, all based on population-based cancer registries. Trends were reported on average for 18 years. Overall pooled estimates of the annual percentage change (APC) were 1.4 (95% confidence interval [CI] 0.5, 2.3) for childhood liver cancers, 2.8 (95% CI 1.8, 3.8) for hepatoblastoma and -3.0 (95% CI -11.0, 4.9) for hepatocellular carcinoma. Sub-group analysis by region indicated increasing trends for childhood liver cancers in North America/Europe/Australia (APC 1.7, 95% CI 0.7, 2.8) whereas corresponding trends were stable in Asia (APC 1.4, 95%CI -0.3, 2.7). Publication bias was not detected for any of these analyses. The I2 statistic indicated that the heterogeneity among included studies was low for combined liver cancers, moderate for hepatoblastoma and high for hepatocellular carcinoma. CONCLUSIONS: Incidence is increasing for childhood liver cancers and the most commonly diagnosed subgroup hepatoblastoma. Lack of knowledge of the etiology of childhood liver cancers limited the ability to understand the reasons for observed incidence trends. This review highlighted the need for ongoing monitoring of incidence trends and etiological studies.

Comparing multilevel and Bayesian spatial random effects survival models to assess geographical inequalities in colorectal cancer survival: a case study.

BACKGROUND: Multilevel and spatial models are being increasingly used to obtain substantive information on area-level inequalities in cancer survival. Multilevel models assume independent geographical areas, whereas spatial models explicitly incorporate geographical correlation, often via a conditional autoregressive prior. However the relative merits of these methods for large population-based studies have not been explored. Using a case-study approach, we report on the implications of using multilevel and spatial survival models to study geographical inequalities in all-cause survival. METHODS: Multilevel discrete-time and Bayesian spatial survival models were used to study geographical inequalities in all-cause survival for a population-based colorectal cancer cohort of 22,727 cases aged 20-84 years diagnosed during 1997-2007 from Queensland, Australia. RESULTS: Both approaches were viable on this large dataset, and produced similar estimates of the fixed effects. After adding area-level covariates, the between-area variability in survival using multilevel discrete-time models was no longer significant. Spatial inequalities in survival were also markedly reduced after adjusting for aggregated area-level covariates. Only the multilevel approach however, provided an estimation of the contribution of geographical variation to the total variation in survival between individual patients. CONCLUSIONS: With little difference observed between the two approaches in the estimation of fixed effects, multilevel models should be favored if there is a clear hierarchical data structure and measuring the independent impact of individual- and area-level effects on survival differences is of primary interest. Bayesian spatial analyses may be preferred if spatial correlation between areas is important and if the priority is to assess small-area variations in survival and map spatial patterns. Both approaches can be readily fitted to geographically enabled survival data from international settings.

An analysis of competing mortality risks among colorectal cancer survivors in Queensland, 1996-2009.

PURPOSE: Colorectal cancer survivors are at risk of dying from other causes including comorbidities and second malignancies. This study was undertaken to identify demographic and clinical predictors of cancer-specific and competing causes of mortality. METHODS: The crude probabilities of mortality attributed to colorectal cancer, other cancers, and non-cancer causes were estimated for 19,415 residents of Queensland, Australia, who were diagnosed with a first primary colorectal cancer between 1996 and 2007 when aged 20-79 years and survived at least 2 months, with follow-up to the end of 2009. Multivariate competing risk analysis was used to analyze covariate effects on the cumulative probability of the different mortality types. RESULTS: Five-year cumulative probabilities of colorectal cancer, other cancers, and non-cancer mortality were 29.4 % (95 % CI 29.3, 30.7), 2.0 % (95 % CI 1.8, 2.2), and 5.7 % (95 % CI 5.3, 6.0), respectively. Factors associated with an increased risk of non-cancer mortality included older age, male gender, unmarried status, localized disease, first primary colon cancers, no surgery, and the presence of comorbidities. Apart from diagnosis of a metachronous secondary cancer, being older, unmarried, or in blue-collar occupations were independent predictors of increased mortality due to other cancers. CONCLUSIONS: A better understanding of the role of competing events and the ability to predict risk of such events have the potential to translate into more effective individualized strategies for colorectal cancer management. The control of comorbidities and reducing cancer risk through clinical management and lifestyle changes should be an important and attainable goal for CRC survivors.

Geographic remoteness, area-level socioeconomic disadvantage and inequalities in colorectal cancer survival in Queensland: a multilevel analysis.

BACKGROUND: To explore the impact of geographical remoteness and area-level socioeconomic disadvantage on colorectal cancer (CRC) survival. METHODS: Multilevel logistic regression and Markov chain Monte Carlo simulations were used to analyze geographical variations in five-year all-cause and CRC-specific survival across 478 regions in Queensland Australia for 22,727 CRC cases aged 20-84 years diagnosed from 1997-2007. RESULTS: Area-level disadvantage and geographic remoteness were independently associated with CRC survival. After full multivariate adjustment (both levels), patients from remote (odds Ratio [OR]: 1.24, 95%CrI: 1.07-1.42) and more disadvantaged quintiles (OR=1.12, 1.15, 1.20, 1.23 for Quintiles 4, 3, 2 and 1 respectively) had lower CRC-specific survival than major cities and least disadvantaged areas. Similar associations were found for all-cause survival. Area disadvantage accounted for a substantial amount of the all-cause variation between areas. CONCLUSIONS: We have demonstrated that the area-level inequalities in survival of colorectal cancer patients cannot be explained by the measured individual-level characteristics of the patients or their cancer and remain after adjusting for cancer stage. Further research is urgently needed to clarify the factors that underlie the survival differences, including the importance of geographical differences in clinical management of CRC.

A Review of the Application of Spatial Survival Methods in Cancer Research: Trends, Modeling, and Visualization Techniques.

Spatial modeling of cancer survival is an important tool for identifying geographic disparities and providing an evidence base for resource allocation. Many different approaches have attempted to understand how survival varies geographically. This is the first scoping review to describe different methods and visualization techniques and to assess temporal trends in publications. The review was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline using PubMed and Web of Science databases. Two authors independently screened articles. Articles were eligible for review if they measured cancer survival outcomes in small geographical areas by using spatial regression and/or mapping. Thirty-two articles were included, and the number increased over time. Most articles have been conducted in high-income countries using cancer registry databases. Eight different methods of modeling spatial survival were identified, and there were seven different ways of visualizing the results. Increasing the use of spatial modeling through enhanced data availability and knowledge sharing could help inform and motivate efforts to improve cancer outcomes and reduce excess deaths due to geographical inequalities. Efforts to improve the coverage and completeness of population-based cancer registries should continue to be a priority, in addition to encouraging the open sharing of relevant statistical programming syntax and international collaborations.

Geographical and spatial variations in bowel cancer screening participation, Australia, 2015-2020.

BACKGROUND: Participation in bowel cancer screening programs remains poor in many countries. Knowledge of geographical variation in participation rates may help design targeted interventions to improve uptake. This study describes small-area and broad geographical patterns in bowel screening participation in Australia between 2015-2020. METHODS: Publicly available population-level participation data for Australia's National Bowel Cancer Screening Program (NBCSP) were modelled using generalized linear models to quantify screening patterns by remoteness and area-level disadvantage. Bayesian spatial models were used to obtain smoothed estimates of participation across 2,247 small areas during 2019-2020 compared to the national average, and during 2015-2016 and 2017-2018 for comparison. Spatial heterogeneity was assessed using the maximized excess events test. RESULTS: Overall, screening participation rates was around 44% over the three time-periods. Participation was consistently lower in remote or disadvantaged areas, although heterogeneity was evident within these broad categories. There was strong evidence of spatial differences in participation over all three periods, with little change in patterns between time periods. If the spatial variation was reduced (so low participation areas were increased to the 80th centile), an extra 250,000 screens (4% of total) would have been conducted during 2019-2020. CONCLUSIONS: Despite having a well-structured evidence-based government funded national bowel cancer screening program, the substantial spatial variation in participation rates highlights the importance of accounting for the unique characteristics of specific geographical regions and their inhabitants. Identifying the reasons for geographical disparities could inform interventions to achieve more equitable access and a higher overall bowel screening uptake.

Multilevel determinants of breast cancer survival: association with geographic remoteness and area-level socioeconomic disadvantage.

A major priority for cancer control agencies is to reduce geographical inequalities in cancer outcomes. While the poorer breast cancer survival among socioeconomically disadvantaged women is well established, few studies have looked at the independent contribution that area- and individual-level factors make to breast cancer survival. Here, we examine relationships between geographic remoteness, area-level socioeconomic disadvantage and breast cancer survival after adjustment for patients' socio-demographic characteristics and stage at diagnosis. Multilevel logistic regression and Markov chain Monte Carlo simulation were used to analyze 18,568 breast cancer cases extracted from the Queensland Cancer Registry for women aged 30-70 years diagnosed between 1997 and 2006 from 478 Statistical Local Areas in Queensland, Australia. Independent of individual-level factors, area-level disadvantage was associated with breast cancer survival (P = 0.032). Compared to women in the least disadvantaged quintile (quintile 5), women diagnosed while resident in one of the remaining four quintiles had significantly worse survival (OR 1.23, 1.27, 1.30, 1.37 for quintiles 4, 3, 2, and 1, respectively). Geographic remoteness was not related to lower survival after multivariable adjustment. There was no evidence that the impact of area-level disadvantage varied by geographic remoteness. At the individual-level, Indigenous status, blue collar occupations and advanced disease were important predictors of poorer survival. A woman's survival after a diagnosis of breast cancer depends on the socio-economic characteristics of the area where she lives, independently of her individual-level characteristics. It is crucial that the underlying reasons for these inequalities be identified to appropriately target policies, resources and effective intervention strategies.

Multiple primary cancers among colorectal cancer survivors in Queensland, Australia, 1996-2007.

PURPOSE: To quantify the demographic and clinical factors associated with an increased risk of multiple primary cancers (MPCs) among colorectal cancer survivors. METHODS: Standardized incidence ratios for MPCs were calculated for residents of Queensland, Australia, who were diagnosed with a first primary colorectal cancer between 1996 and 2005 and survived for at least 2 months. Relative risk ratios were calculated for all MPCs combined and selected individual sites using multivariate Poisson models. RESULTS: A total of 1,615 MPCs were observed among 15,755 study patients. The cohort had a significant excess risk of developing subsequent colorectal (SIR = 1.47, 95 % CI 1.30-1.66) or non-colorectal (SIR = 1.24, 95 % CI 1.18-1.31) cancers relative to the incidence of cancer in the general population. Age at initial diagnosis, follow-up time, initial colorectal subsite, and surgical treatment were independently associated (p < 0.01) with the overall risk of developing MPCs after adjustment. The relative risk ratio was 1.23 (95 % CI 1.07-1.41) for those aged 20-59 years compared with the 70-79 age group and 0.82 (95 % CI 0.72-0.92) for 1-5-year follow-up relative to the first year. The likelihood of being diagnosed with a MPC was 33 % higher (95 % CI 1.12-1.56) for surgically treated patients and 45 % higher (95 % CI 1.29-1.64) after proximal colon cancers relative to rectal cancer. CONCLUSIONS: While these population-based results do not incorporate all possible risk factors, they form an important foundation from which to further investigate the etiological causes that result in the development of MPCs among colorectal cancer survivors.

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.

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.

Distance to the closest radiotherapy facility and survival after a diagnosis of rectal cancer in Queensland.

OBJECTIVE: To determine whether an association exists between distance from radiotherapy facilities and survival outcomes of people diagnosed with rectal cancer. DESIGN AND SETTING: Descriptive population-based study using data from the Queensland Cancer Registry. PATIENTS: All patients aged 20-79 years (n = 6848) diagnosed with invasive rectal cancer between 1 January 1996 and 31 December 2006. MAIN OUTCOME MEASURE: Cause-specific survival. RESULTS: The 5-year cause-specific survival was 62% (95% CI, 61%-64%); it was strongly influenced by stage at diagnosis (American Joint Committee on Cancer, Stages I-IV), ranging from 86% (Stage I) to 9% (Stage IV). After adjusting for age, sex, and stage at diagnosis, patients who lived 100-199 km, 200-399 km and 400 km or more from a radiotherapy facility were 16%, 30%, and 25%, respectively, more likely to die from rectal cancer than patients living within 50 km of such a facility. On average, there was a 6% increase in mortality risk (95% CI, 3%-8%; P < 0.001) for each 100 km increment in distance from the nearest radiotherapy facility. Shared frailty models showed that this association persisted after adjusting for the correlation between individual cancer patients living in the same remoteness or area-level socioeconomic status categories. CONCLUSIONS: While centralisation of cancer treatment services has merit, our study provides evidence of a shorter survival for people with rectal cancer who live relatively far from radiotherapy facilities. It remains a priority to develop and implement policy, cultural and clinical measures to reduce the burden faced by rural and remote patients with rectal cancer.

A systematic review and meta-analysis on international studies of prevalence, mortality and survival due to coal mine dust lung disease.

BACKGROUND: Coal mine dust lung disease comprises a group of occupational lung diseases including coal workers pneumoconiosis. In many countries, there is a lack of robust prevalence estimates for these diseases. Our objective was to perform a systematic review and meta-analysis of published contemporary estimates on prevalence, mortality, and survival for coal mine dust lung disease worldwide. METHODS: Systematic searches of PubMed, EMBASE and Web of Science databases for English language peer-reviewed articles published from 1/1/2000 to 30/03/2021 that presented quantitative estimates of prevalence, mortality, or survival for coal mine dust lung disease. Review was conducted per PRISMA guidelines. Articles were screened independently by two authors. Studies were critically assessed using Joanna Briggs Institute tools. Pooled prevalence estimates were obtained using random effects meta-analysis models. Heterogeneity was measured using the I2 statistics and publication bias using Egger's tests. RESULTS: Overall 40 studies were included, (31 prevalence, 8 mortality, 1 survival). Of the prevalence estimates, fifteen (12 from the United States) were retained for the meta-analysis. The overall pooled prevalence estimate for coal workers pneumoconiosis among underground miners was 3.7% (95% CI 3.0-4.5%) with high heterogeneity between studies. The pooled estimate of coal workers pneumoconiosis prevalence in the United States was higher in the 2000s than in the 1990s, consistent with published reports of increasing prevalence following decades of declining trends. Sub-group analyses also indicated higher prevalence among underground miners, and in Central Appalachia. The mortality studies were suggestive of reduced pneumoconiosis mortality rates over time, relative to the general population. CONCLUSION: The ongoing prevalence of occupational lung diseases among contemporary coal miners highlights the importance of respiratory surveillance and preventive efforts through effective dust control measures. Limited prevalence studies from countries other than the United States limits our understanding of the current disease burden in other coal-producing countries.

Crude probability of death for cancer patients by spread of disease in New South Wales, Australia 1985 to 2014.

BACKGROUND: To estimate trends in the crude probability of death for cancer patients by sex, age and spread of disease over the past 30 years in New South Wales, Australia. METHODS: Population-based cohort of 716,501 people aged 15-89 years diagnosed with a first primary cancer during 1985-2014 were followed up to 31 December 2015. Flexible parametric relative survival models were used to estimate the age-specific crude probability of dying from cancer and other causes by calendar year, sex and spread of disease for all solid tumours combined and cancers of the colorectum, lung, female breast, prostate and melanoma. RESULTS: Estimated 10-year sex, age and spread-specific crude probabilities of cancer death generally decreased over time for most cancer types, although the magnitude of the decrease varied. For example, out of 100 fifty-year old men with localized prostate cancer, 12 would have died from their cancer if diagnosed in 1985 and 3 in 2014. Greater degree of spread was consistently associated with higher probability of dying from cancer, although outcomes for lung cancer were consistently poor. For both males and females, the probability of non-cancer deaths was higher among older patients, those diagnosed with localized cancers and where cancer survival was higher. CONCLUSION: Crude probabilities presented here may be useful in helping clinicians and their patients better understand prognoses and make informed decisions about treatment. They also provide novel insights into the relative contributions that early detection and improved treatments have on the observed temporal patterns in cancer survival.

Temporal and area-level variation in prevalence of high-grade histologically confirmed cervical abnormalities among Indigenous and non-Indigenous women, Queensland, Australia, 2008-2017.

OBJECTIVE: Despite Australia's National Cervical Screening Program, Indigenous women have a disproportionately high burden of cervical cancer. We describe temporal and area-level patterns in prevalence of histologically conformed high-grade cervical abnormalities (hHGA) among cytologically screened women by Indigenous status. METHODS: This was a population-based study of 2,132,925 women, aged 20-69, who underwent cervical screening between 2008 and 2017, in Queensland, Australia. Of these, 47,136 were identified as Indigenous from linked hospital records. Overall patterns in hHGA prevalence by Indigenous status were quantified using prevalence rate ratios (PrRR) from negative binomial models. Bayesian spatial models were used to obtain smoothed prevalence estimates of hHGA across 528 small areas compared to the state average. Results are presented as maps and graphs showing the associated uncertainty of the estimates. RESULTS: Overall, screened Indigenous women had significantly higher hHGA prevalence than non-Indigenous women. However, the magnitude of the difference reduced over time (p < 0.001). Adjusted for age and area-level variables, Indigenous women had 36% higher hHGA prevalence (PrRR 1.36, 95% confidence interval [1.21-1.52]) than non-Indigenous women between 2013 and 2017. The overall effect of age decreased over time (p = 0.021). Although there was evidence of moderate spatial variation in 10-year prevalence estimates for both groups of women, the high levels of uncertainty for many estimates, particularly for Indigenous women, limited our ability to draw definitive conclusions about the spatial patterns. CONCLUSIONS: While the temporal reduction in Indigenous: non-Indigenous differential in hHGA prevalence is encouraging, further research into the key drivers of the continuing higher risk among Indigenous women is warranted.

Access to Aboriginal Community-Controlled Primary Health Organizations Can Explain Some of the Higher Pap Test Participation Among Aboriginal and Torres Strait Islander Women in North Queensland, Australia.

BACKGROUND: Aboriginal and Torres Strait Islander Community-Controlled Health Organisations (ACCHOs) provides culturally appropriate primary care for Aboriginal and Torres Strait Islander people in Australia. The population of North Queensland has a higher proportion of Aboriginal and Torres Strait Islander people, a greater population coverage of ACCHOs, and higher cervical screening participation than the Rest of Queensland. The association between regional differences in the use of ACCHOs for cervical screening and variations in screening participation among Aboriginal and Torres Strait Islander women is currently unknown. METHODS: This is a population-based study of 1,107,233 women, aged 20-69 years who underwent cervical screening between 2013 and 2017. Of these women, 132,972 (12%) were from North Queensland, of which 9% were identified as Aboriginal and Torres Strait Islander women (2% Rest of Queensland) through linkage to hospital records. Regional differentials in screening by Aboriginal and Torres Strait Islander status were quantified using participation rate ratios (PRRs) with 95% confidence intervals (CIs) from negative binomial regression models. Logistic regression was used to identify factors associated with Aboriginal and Torres Strait Islander women being screened at ACCHOs. RESULTS: Aboriginal and Torres Strait Islander women from North Queensland (versus) Rest of Queensland had higher odds of screening at ACCHOs after adjusting for age and area-level variables. After adjustment for non-ACCHO variables, the regional differential in screening among Aboriginal and Torres Strait Islander women was significantly higher (PRR 1.28, 95% CI 1.20-1.37) than that among other Australian women [PRR = 1.11 (1.02-1.18)], but was attenuated on further adjustment for ACCHO variables, [PRR = 1.15, (1.03-1.28)] to become similar to the corresponding point estimate for other Australian women [PRR = 1.09, (1.01-1.20)]. However, the significant interaction between Aboriginal and Torres Strait Islander status and region (p < 0.001) remained, possibly reflecting the large cohort size. Screening participation increased with better access to health services for all women. CONCLUSIONS: Improving access to primary health care for Aboriginal and Torres Strait Islander women, especially through ACCHOs, may reduce existing disparities in cervical screening participation. Further gains will require greater levels of local community engagement and understanding of the experiences of screened Aboriginal and Torres Strait Islander women to inform effective interventions.

Impact of area-level socioeconomic status and accessibility to treatment on life expectancy after a cancer diagnosis in Queensland, Australia.

AIMS: This study quantifies geographic inequities in loss of life expectancy (LOLE) by area-level socioeconomic status (SES) and accessibility to treatment. METHODS: Analysis was conducted using a population-based cancer-registry cohort (n = 371,570) of Queensland (Australia) residents aged 50-89 years, diagnosed between 1997-2016. Flexible parametric survival models were used to estimate LOLE by area-level SES and accessibility for all invasive cancers and the five leading cancers. The gain in life years that could be achieved if all cancer patients experienced the same relative survival as those in the least disadvantaged-high accessibility category was estimated for the 2016 cohort. RESULTS: For all invasive cancers, men living in the most disadvantaged areas lost 34 % of life expectancy due to their cancer diagnosis, while those from the least disadvantaged areas lost 25 %. The corresponding percentages for women were 33 % and 23 %. Accessibility had a lower impact on LOLE than SES, with patients from low accessibility areas losing 0-4 % more life expectancy than those from high accessibility areas. For cancer patients diagnosed in 2016 (n = 24,423), an estimated 101,387 life years will be lost. This would be reduced by 19 % if all patients experienced the same relative survival as those from the least disadvantaged-high accessibility areas. CONCLUSION: The impact of a cancer diagnosis on remaining life expectancy varies by geographical area. Establishing reasons why area disadvantage impacts on life expectancy is crucial to inform subsequent interventions that could increase the life expectancy of cancer patients from more disadvantaged areas.

Quantifying the Number of Cancer Deaths Avoided Due to Improvements in Cancer Survival since the 1980s in the Australian Population, 1985-2014.

BACKGROUND: This study quantifies the number of potentially "avoided"cancer deaths due to differences in 10-year relative survival between three time periods, reflecting temporal improvements in cancer diagnostic and/or treatment practices in Australia. METHODS: National population-based cohort of 2,307,565 Australians ages 15 to 89 years, diagnosed with a primary invasive cancer from 1985 to 2014 with mortality follow-up to December 31, 2015. Excess mortality rates and crude probabilities of cancer deaths were estimated using flexible parametric relative survival models. Crude probabilities were then used to calculate "avoided cancer deaths" (reduced number of cancer deaths within 10 years of diagnosis due to survival changes since 1985-1994) for all cancers and 13 leading cancer types. RESULTS: For each cancer type, excess mortality (in the cancer cohort vs. the expected population mortality) was significantly lower for more recently diagnosed persons. For all cancers combined, the number of "avoided cancer deaths" (vs. 1985-1994) was 4,877 (1995-2004) and 11,385 (2005-2014) among males. Prostate (1995-2004: 2,144; 2005-2014: 5,099) and female breast cancer (1,127 and 2,048) had the highest number of such deaths, whereas <400 were avoided for pancreatic or lung cancers across each period. CONCLUSIONS: Screening and early detection likely contributed to the high number of "avoided cancer deaths" for prostate and female breast cancer, whereas early detection remains difficult for lung and pancreatic cancers, highlighting the need for improved preventive and screening measures. IMPACT: Absolute measures such as "avoided cancer deaths" can provide a more tangible estimate of the improvements in cancer survival than standard net survival measures.