Individual and area level factors associated with the breast cancer diagnostic-treatment interval in Queensland, Australia

BACKGROUND

Delays to breast cancer treatment can lead to more aggressive and extensive treatments, increased expenses, increased psychological distress, and poorer survival. We explored the individual and area level factors associated with the interval between diagnosis and first treatment in a population-based cohort in Queensland, Australia.

METHODS

Data from 3216 Queensland women aged 20 to 79, diagnosed with invasive breast cancer (ICD-O-3 C50) between March 2010 and June 2013 were analysed. Diagnostic dates were sourced from the Queensland Cancer Registry and treatment dates were collected via self-report. Diagnostics-treatment intervals were modelled using flexible parametric survival methods.

RESULTS

The median interval between breast cancer diagnosis and first treatment was 15 days, with an interquartile range of 9-26 days. Longer diagnostic-treatment intervals were associated with a lack of private health coverage, lower pre-diagnostic income, first treatments other than breast conserving surgery, and residence outside a major city. The model explained a modest 13.7% of the variance in the diagnostic-treatment interval [Formula: see text]. Sauerbrei's D was 0.82, demonstrating low to moderate discrimination performance.

CONCLUSION

Whilst this study identified several individual- and area-level factors associated with the time between breast cancer diagnosis and first treatment, much of the variation remained unexplained. Increased socioeconomic disadvantage appears to predict longer diagnostic-treatment intervals. Though some of the differences are small, many of the same factors have also been linked to screening and diagnostic delay. Given the potential for accumulation of delay at multiple stages along the diagnostic and treatment pathway, identifying and applying effective strategies address barriers to timely health care faced by socioeconomically disadvantaged women remains a priority.

Disease mapping: Geographic differences in population rates of interventional treatment for prostate cancer in Australia

BACKGROUND

Treatment decisions for men diagnosed with prostate cancer depend on a range of clinical and patient characteristics such as disease stage, age, general health, risk of side effects and access. Associations between treatment patterns and area-level factors such as remoteness and socioeconomic disadvantage have been observed in many countries.

OBJECTIVE

To model spatial differences in interventional treatment rates for prostate cancer at high spatial resolution to inform policy and decision-making.

METHODS

Hospital separations data for interventional treatments for prostate cancer (radical prostatectomy, low dose rate and high dose rate brachytherapy) for men aged 40 years and over were modelled using spatial models, generalised linear mixed models, maximised excess events tests and k-means statistical clustering.

RESULTS

Geographic differences in population rates of interventional treatments were found (p<0.001). Separation rates for radical prostatectomy were lower in remote areas (12.2 per 10 000 person-years compared with 15.0-15.9 in regional and major city areas). Rates for all treatments decreased with increasing socioeconomic disadvantage (radical prostatectomy 19.1 /10 000 person-years in the most advantaged areas compared with 12.9 in the most disadvantaged areas). Three groups of similar areas were identified: those with higher rates of radical prostatectomy, those with higher rates of low dose brachytherapy, and those with low interventional treatment rates but higher rates of excess deaths. The most disadvantaged areas and remote areas tended to be in the latter group.

CONCLUSIONS

The geographic differences in treatment rates may partly reflect differences in patients' physical and financial access to treatments. Treatment rates also depend on diagnosis rates and thus reflect variation in investigation rates for prostate cancer and presentation of disease. Spatial variation in interventional treatments may aid identification of areas of under-treatment or over-treatment.

Treatment intervals and survival for women diagnosed with early breast cancer in Queensland: the Breast Cancer Outcomes Study, a population-based cohort study

OBJECTIVES

To assess associations between breast cancer-specific survival and timeliness of treatment, based on 2020 Australian guidelines for the treatment of early breast cancer.

DESIGN

Population-based cohort study; analysis of linked Queensland Cancer Register, patient medical record, and National Death Index data, supplemented by telephone interviews.

SETTING, PARTICIPANTS

Women aged 20-79 years diagnosed with invasive breast cancer during 1 March 2010 - 30 June 2013, followed to 31 December 2020.

MAIN OUTCOME MEASURES

Breast cancer-specific survival for women who received or did not receive treatment within the recommended timeframe, overall and for six treatment intervals; optimal cut-points for each treatment interval; characteristics of women for whom treatment was not provided within the recommended timeframe.

RESULTS

Of 5426 eligible women, 4762 could be invited for interviews; complete data were available for 3044 women (56% of eligible women, 65% of invited women). Incomplete compliance with guideline interval recommendations was identified for 1375 women (45%); their risk of death from breast cancer during the follow-up period was greater than for those for whom guideline compliance was complete (adjusted hazard ratio [aHR], 1.43; 95% confidence interval [CI], 1.04-1.96). Risk of death was greater for women for whom the diagnosis to surgery interval exceeded 29 days (aHR, 1.76; 95% CI, 1.19-2.59), the surgery to chemotherapy interval exceeded 36 days (aHR, 1.63; 95% CI, 1.13-2.36), or the chemotherapy to radiotherapy interval exceeded 31 days (aHR, 1.83; 95% CI, 1.19-2.80). Treatment intervals longer than recommended were more frequent for women for whom breast cancer was detected by public facility screening (adjusted odds ratio [aOR], 1.58; 95% CI, 1.22-2.04) or by symptoms (aOR, 1.39; 95% CI, 1.09-1.79) than when cancer had been detected in private facilities, and for women without private health insurance (aOR, 1.96; 95% CI, 1.66-2.32) or living outside major cities (aOR, 1.38; 95% CI, 1.18-1.62).

CONCLUSIONS

Breast cancer-specific survival was poorer for women for whom the diagnosis to surgery, surgery to chemotherapy, or chemotherapy to radiotherapy intervals exceeded guideline-recommended limits. Our findings support 2020 Australian guideline recommendations regarding timely care.

Temporal changes in childhood cancer incidence and survival by stage at diagnosis in Australia, 2000-2017

BACKGROUND

The Toronto Paediatric Cancer Stage Guidelines are a compendium of staging systems developed to facilitate collection of consistent and comparable data on stage at diagnosis for childhood cancers by cancer registries.

MATERIAL AND METHODS

This retrospective, observational cohort study investigated changes in stage-specific incidence and survival for children diagnosed between 2000-2008 compared to 2009-2017 using the population-based Australian Childhood Cancer Registry. Information on mortality for each patient was available to 31st December 2020. Shifts in incidence by stage were evaluated using chi-square tests, and differences in stage-specific five-year observed survival for all causes of death over time were assessed using flexible parametric models.

RESULTS

Stage was assigned according to the Toronto Guidelines for 96% (n = 7944) of the total study cohort (n = 8292). Changes in the distribution of incidence by stage between the two diagnosis periods were observed for retinoblastoma, with stage 0 increasing from 26% to 37% of cases (p = 0.02), and hepatoblastoma, with metastatic disease increasing from 22% to 39% of cases (p = 0.04). There were large gains in stage-specific survival over time for stage IV rhabdomyosarcoma (five-year adjusted mortality hazard ratio for 2009-2017 compared to 2000-2008 of 0.38, 95% CI 0.19-0.77; p = 0.01), stage M3 for medulloblastoma (HR = 0.41, 95% CI 0.21-0.79; p = 0.01) and metastatic neuroblastoma excluding stage MS (HR = 0.61, 95% CI 0.44-0.84; p < 0.01).

CONCLUSION

These results indicate that improvements in childhood cancer survival in Australia are most likely due to refined management rather than changes in stage at diagnosis, particularly for metastatic solid tumours. Wide international uptake of the Toronto Guidelines will allow comprehensive evaluation of differences in survival between countries.

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.

A review of the application of spatial survival methods in cancer research: trends, modelling and visualization techniques

Spatial modelling 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 PRISMA 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 modelling spatial survival were identified, and there were seven different ways of visualizing the results. Increasing the use of spatial modelling 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 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.

Changes in prostate specific antigen (PSA) "screening" patterns by geographic region and socio-economic status in Australia: Analysis of medicare data in 50-69 year old men

BACKGROUND

While it is known that national PSA testing rates have decreased in Australia since 2007, it is not known whether these trends are consistent by broad geographical areas, nor whether previously reported area-specific differences have remained in more recent time periods.

METHODS

Population-based cohort study of Australian men (n = 2793,882) aged 50-69 who received at least one PSA test (Medicare Benefit Schedule item number 66655) during 2002-2018. Outcome measures included age-standardised participation rate, annual percentage change using JoinPoint regression and indirectly standardised participation rate ratio using multivariable Poisson regression.

RESULTS

During 2005-09, two thirds (68%) of Australian men aged 50-69 had at least one PSA test, reducing to about half (48%) during 2014-18. In both periods, testing rates were highest among men living in major cities, men aged 50-59 years, and among men living in the most advantaged areas. Nationally, the Australian PSA testing rate increased by 9.2% per year between 2002 and 2007, but then decreased by 5.0% per year to 2018. This pattern was generally consistent across States and Territories, and socio-economic areas, however the magnitude of the trends was less pronounced in remote and very remote areas.

CONCLUSIONS

The decreasing trends are consistent with a greater awareness of the current guidelines for clinical practice in Australia, which recommend a PSA test be done only with the informed consent of individual men who understand the potential benefits and risks. However, given there remain substantial geographical disparities in prostate cancer incidence and survival in Australia, along with the equivocal evidence for any benefit from PSA screening, there remains a need for more effective diagnostic strategies for prostate cancer to be implemented consistently regardless of where men live.

Spatial patterns of prostate-specific antigen testing in asymptomatic men across Australia: a population-based cohort study, 2017-2018

OBJECTIVES

In Australia, while prostate-specific antigen (PSA) testing rates vary by broad area-based categories of remoteness and socio-economic status, little is known about the extent of variation within them. This study aims to describe the small-area variation in PSA testing across Australia.

STUDY DESIGN

This was a retrospective population-based cohort study.

METHODS

We received data for PSA testing from the Australian Medicare Benefits Schedule. The cohort included men (n = 925,079) aged 50-79 years who had at least one PSA test during 2017-2018. A probability-based concordance was applied across multiple iterations (n = 50) to map each postcode to small areas (Statistical Areas 2; n = 2,129). For each iteration, a Bayesian spatial Leroux model was used to generate smoothed indirectly standardized incidence ratios across each small area, with estimates combined using model averaging.

RESULTS

About a quarter (26%) of the male population aged 50-79 years had a PSA test during 2017-2018. Testing rates among small areas varied 20-fold. Rates were higher (exceedance probability>0.8) compared with the Australian average in the majority of small areas in southern Victoria and South Australia, south-west Queensland, and some coastal regions of Western Australia but lower (exceedance probability<0.2) in Tasmania and Northern Territory.

CONCLUSIONS

The substantial geographical variation in PSA testing rates across small areas of Australia may be influenced by differences in access to and guidance provided by clinicians and attitudes and preferences of men. Greater understanding of PSA testing patterns by subregions and how these patterns relate to health outcomes could inform evidence-based approaches to identifying and managing prostate cancer risk.

Severity and risk factors of interval breast cancer in Queensland, Australia: a population-based study

BACKGROUND

Interval breast cancers (BC) are those diagnosed within 24 months of a negative mammogram. This study estimates the odds of being diagnosed with high-severity BC among screen-detected, interval, and other symptom-detected BC (no screening history within 2 years); and explores factors associated with being diagnosed with interval BC.

METHODS

Telephone interviews and self-administered questionnaires were conducted among women (n = 3,326) diagnosed with BC in 2010-2013 in Queensland. Respondents were categorised into screen-detected, interval, and other symptom-detected BCs. Data were analysed using logistic regressions with multiple imputation.

RESULTS

Compared with screen-detected BC, interval BC had higher odds of late-stage (OR = 3.50, 2.9-4.3), high-grade (OR = 2.36, 1.9-2.9) and triple-negative cancers (OR = 2.55, 1.9-3.5). Compared with other symptom-detected BC, interval BC had lower odds of late stage (OR = 0.75, 0.6-0.9), but higher odds of triple-negative cancers (OR = 1.68, 1.2-2.3). Among women who had a negative mammogram (n = 2,145), 69.8% were diagnosed at their next mammogram, while 30.2% were diagnosed with an interval cancer. Those with an interval cancer were more likely to have healthy weight (OR = 1.37, 1.1-1.7), received hormone replacement therapy (2-10 years: OR = 1.33, 1.0-1.7; > 10 years: OR = 1.55, 1.1-2.2), conducted monthly breast self-examinations (BSE) (OR = 1.66, 1.2-2.3) and had previous mammogram in a public facility (OR = 1.52, 1.2-2.0).

CONCLUSION

These results highlight the benefits of screening even among those with an interval cancer. Women-conducted BSE were more likely to have interval BC which may reflect their increased ability to notice symptoms between screening intervals.

Long-term childhood cancer survival in Australia using period estimation

Estimates of childhood cancer survival are usually reported at 5 years after diagnosis only. Using cases prevalent between 2014 and 2018 from the population-based Australian Childhood Cancer Registry, we used the period method to calculate relative survival up to 20 years post diagnosis by cancer type. Twenty-year relative survival for all childhood cancers combined (n = 14,353) was 83.8% (95% confidence interval [CI] = 82.6%-85.0%). Survival decreased only slightly after 10 years for most childhood cancers, except for some types of brain and liver tumours. These contemporary estimates of long-term survival provide valuable information to assist childhood cancer patients and their families in planning for the future.

Childhood cancer survival and avoided deaths in Australia, 1983-2016

BACKGROUND

Large improvements in childhood cancer survival have been reported over recent decades. Data from cancer registries have the advantage of providing a 'whole of population' approach to gauge the success of cancer control efforts.

OBJECTIVES

The aim of this study was to investigate recent survival estimates for children diagnosed with cancer Australia and to examine the extent of changes in survival over the last 35 years. For the first time, we also estimated the number of deaths among Australian children that were potentially avoided due to improvements in survival.

METHODS

A retrospective, population-based cohort study design was used. Case information was extracted from the Australian Childhood Cancer Registry for 1983-2016, with follow-up to 31 December 2017. Eligible children were aged 0-14 with a basis of diagnosis other than autopsy or death certificate only. Five-year relative survival was calculated using the semi-complete cohort method for three diagnosis periods (1983-1994, 1995-2006 and 2007-2016), and changes in survival over time were assessed via flexible parametric models. Avoided deaths within 5 years for those diagnosed between 1995 and 2016 were estimated under the assumption that survival rates remained the same as for 1983-1994.

RESULTS

Overall 5-year survival within the study cohort (n = 20,871) increased from 72.8% between 1983 and1994 to 86.1% between 2007 and 2016, equating to an adjusted excess mortality hazard ratio of 1.82 (95% confidence interval 1.67, 1.97). Most cancers showed improvements in survival; other gliomas, hepatoblastoma and osteosarcoma were exceptions. Among children diagnosed between 1995 and 2016, 38.7% of expected deaths within 5 years of diagnosis (n = 1537 of 3970) were avoided due to temporal improvements in survival.

CONCLUSIONS

Survival for childhood cancer has continued to improve over recent years, thanks mainly to ongoing progress in treatment development combined with improved supportive care. Providing innovative measures of survival, such as avoided deaths, may assist with understanding outcome data produced by cancer registries.

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.

Cancer Incidence in Migrants in Australia: Patterns of Three Infection-Related Cancers

BACKGROUND

Australia provides an ideal population-base for cancer migration studies because of its multicultural society and high-quality cancer registrations. Among migrant groups there is considerable variability in the incidence of infection-related cancers; thus, the patterns of three such cancers were examined among migrant groups relative to Australian-born residents.

METHODS

Using national incidence data for cancers of the stomach, liver, and cervix diagnosed during 2005 to 2014, incidence rates were compared for selected migrant groups with the Australian-born population using incidence rate ratios (IRR), from a negative binomial regression model.

RESULTS

Wide variations in incidence between countries/regions of birth were observed for all three cancers (P < 0.0001). The patterns were similar for cancers of the stomach and liver, in that migrants from countries/regions with higher incidence rates maintained an increased risk in Australia, with the highest being among South American migrants (IRR = 2.35) for stomach cancer and among Vietnamese migrants (5.44) for liver cancer. In contrast, incidence rates of cervical cancer were lower for many migrant groups, with women from Southern Asia (0.39) and North Africa (0.42) having the lowest rates. The rate of cervical cancer was higher in migrants from New Zealand, Philippines, and Polynesia.

CONCLUSIONS

Several Australian migrant groups were found to experience a disproportionate burden of infection-related cancers; further studies of associated risk factors may inform the design of effective interventions to mediate these disparities.

IMPACT

By identifying these migrant groups, it is hoped that these results will motivate and inform prevention or early detection activities for these migrant groups. See related commentary Dee and Gomez, p. 1251.

Supportive care needs and psychosocial outcomes of rural versus urban women with breast cancer

OBJECTIVE

To identify whether supportive care needs vary according to remoteness and area-level socio-economic status (SES) and to identify the combinations of socio-demographic, area-level and health factors that are associated with poorer quality of life, psychological distress and severity of unmet supportive care needs METHODS: Cross sectional data was collected from women with a breast cancer diagnosis (n=2,635) in Queensland, Australia, through a telephone survey including socio-demographic, health, psychosocial and supportive care needs measures. Hierarchical regression and cluster analyses were applied to assess the predictors of unmet need and psychosocial outcomes and to identify socio-demographic and health status profiles of women, comparing their level of unmet needs and psychosocial outcomes.

RESULTS

Women living in outer regional areas reported the highest severity of unmet need in the patient care domain. Greater unmet need for health systems and information and patient care was also evident for those in moderately and most disadvantaged areas. Three clusters were identified reflecting (1) older women with poorer health and lower education (19%); (2) younger educated women with better health and private insurance (61%); and (3) physically active women with localised cancer who had completed treatment (20%). Poorer outcomes were evident in the first two of these clusters.

CONCLUSIONS

This better understanding of the combinations of characteristics associated with poorer psychosocial outcomes and higher unmet need can be used to identify women with higher supportive care needs early and to target interventions. This article is protected by copyright. All rights reserved.

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.

Changes in cancer incidence and survival among Aboriginal and Torres Strait Islander children in Australia, 1997-2016

BACKGROUND

This study reports cancer incidence and survival among Aboriginal and Torres Strait Islander children and other Australian children, and assesses changes over time.

PROCEDURE

Data were from the population-based Australian Childhood Cancer Registry. The study comprised children aged under 15 diagnosed between 1997 and 2016 and with mortality follow-up until 31 December 2017. Incidence trends were analysed using JoinPoint regression. Five-year cancer-specific survival was calculated using the semi-complete approach with survival comparisons made using multivariable flexible parametric models.

RESULTS

Aboriginal and Torres Strait Islander children accounted for 506 of 13,299 eligible cases (3.8%). Incidence rates for Aboriginal and Torres Strait Islander children across the study period increased by 2.3% annually (95% confidence interval [CI]: +0.6% to +4.0%) and for other Australian children increased by 0.6% annually (95% CI: +0.3% to +0.9%; p = .05). Nonetheless, cancer incidence was consistently lower for Aboriginal and Torres Strait Islander children, with an incidence rate ratio of 0.73 (95% CI: 0.62-0.85; p < .01) between 2012 and 2016. Survival for Aboriginal and Torres Strait Islander children with solid tumours was 70.6% (95% CI: 62.5%-77.3%) and for other Australian children was 83.5% (95% CI: 82.3%-84.7%; p < .01), with indications of this difference diminishing in recent years.

CONCLUSIONS

Improvements in identification, particularly in urban areas, most likely accounts for the greater increase in cancer incidence rates among Aboriginal and Torres Strait Islander children. Examination of data on stage at diagnosis and treatment may provide important insights into survival for children with solid tumours.

Risk of extracolonic second primary cancers following a primary colorectal cancer: a systematic review and meta-analysis

PURPOSE

The purpose of the study is to assess the global risk of extracolonic secondary primary cancers (SPCs) in patients with colorectal cancer (CRC).

METHODS

Studies of SPC in patients with CRC were included if they reported the standardised incidence ratio (SIR) for extracolonic SPCs in patients with CRC compared with the general population. Pooled summary estimates were calculated using a random-effects model.

RESULTS

A total of 7,716,750 patients with CRC from 13 retrospective cohort studies that reported extracolonic SPC incidence were included. The overall risk of several SPCs was significantly higher in patients with CRC compared with the general population, including cancers of the urinary bladder (pooled SIR 1.19, 95% confidence interval (CI) 1.06-1.33; p = 0.003), female genital tract (1.88, 1.07-3.31; p = 0.03), kidney (1.50, 1.19-1.89; p = 0.0007), thorax (lung, bronchus and mediastinum) (1.16, 1.01-1.32; p = 0.03), small intestine (4.26, 2.58-7.01; p < 0.0001), stomach (1.22, 1.07-1.39; p = 0.003), and thyroid (1.40, 1.28-1.53; p < 0.0001), as well as melanoma (1.28, 1.01-1.62; p = 0.04). There was also a decreased risk of developing cancer of the gall bladder (0.75, 0.60-0.94; p = 0.01).

CONCLUSION

Patients with CRC had a significantly increased risk of extracolonic SPCs compared with the general population. These findings highlight the need to develop research strategies for the management of second primary cancer in patients with CRC.

Tobacco smoking and risk of thyroid cancer according to BRAFV600E mutational subtypes

OBJECTIVE

Smoking has been associated with a reduced risk of thyroid cancer, but whether the association varies between higher- and lower-risk cancers remains unclear. We aimed to assess the association between smoking and risk of thyroid cancer overall as well as by tumour BRAF mutational status as a marker of potentially higher-risk cancer.

DESIGN AND PATIENTS

We recruited 1013 people diagnosed with thyroid cancer and 1057 population controls frequency-matched on age and sex.

METHODS

Multivariable logistic regression was used to assess the association overall and in analyses stratified by tumour characteristics. We used sensitivity analysis to assess the potential for selection bias.

RESULTS

We found little evidence of an association with current smoking (odds ratio [OR] = 0.93; 95% confidence interval [CI]: 0.69-1.26; current vs. never smoking), but a higher number of pack-years of smoking was associated with a lower risk of thyroid cancer (OR = 0.75; 95% CI: 0.57-0.99; ≥20 pack-years vs. never). However, after correcting for potential selection bias, we observed a statistically significant inverse association between current smoking and risk of thyroid cancer (bias-corrected OR = 0.65; 95% CI: 0.51-0.83). Those with BRAF-positive cancers were less likely to be current smokers than those with BRAF-negative cancers (prevalence ratio: 0.79; 95% CI: 0.62-0.99).

CONCLUSION

We found smoking was inversely related to thyroid cancer risk and, in particular, current smoking was associated with a reduced risk of potentially more aggressive BRAF-positive than the likely more indolent BRAF-negative papillary thyroid cancers.

Procedure-specific outcomes following gastrectomy for cancer compared by hospital volume and service capability

BACKGROUND

International literature recommends centralising gastric cancer surgery, however, with volumes that define 'high-volume resection' being higher than those in most major centres in Australia and New Zealand. These reports rarely focus on the difference between total (TG) and partial gastrectomy (PG). We assessed the impact of resection volume and service capability on operative mortality, morbidity and surgical quality in patients who had a PG and TG.

METHODS

Patients who had gastrectomy for adenocarcinoma, between 2001 and 2015, were collected from the Queensland Oncology Repository. Hospitals were characterised by cases-per-annum (high-volume [HV] ≥ 5 and low-volume [LV] < 5) and hospital service capability as (high-service [HS] and low-service [LS]), giving three hospital groups: HVHS, LVHS and LVLS. Chi-squared tests were used to compare post-operative mortality, morbidity, failure to rescue (FTR) from complications and surgical quality between these three groups.

RESULTS

There were 426 patients who had a TG and 827 having PG. HVHS centres performed 59% of PG with high surgical quality rates of: HVHS = 53%, LVHS = 34% and LVLS = 46% (p < 0.01). Surgical complications were highest in LVLS (LVLS = 19%, LVHS = 11%, HVHS = 11%; p = 0.02). There was no difference in 30-day mortality nor in FTR. For TG, HVHS performed 67% of these procedures, with lower 30-day mortality (2%) and FTR rates (5%) compared with LVHS (7%, 22%) and LVLS (12%, 28%; p < 0.01). There was no difference in operative morbidity and surgical quality between hospital groups.

CONCLUSION

Despite the 'high-volume' threshold for gastrectomy being the lowest described in the literature, we have shown that centralisation to HVHS centres was associated with lower operative mortality for TG and improved quality of surgery for PG.

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.

Risk of thyroid cancer following hysterectomy

BACKGROUND

Hysterectomy has been associated with increased thyroid cancer risk but whether this reflects a biological link or increased diagnosis of indolent cancers due to greater medical contact remains unclear.

METHODS

We recruited 730 women diagnosed with thyroid cancer and 785 age-matched population controls. Multivariable logistic regression was used to assess the association overall, and by tumour BRAF mutational status as a marker of potentially higher-risk cancers. We used causal mediation analysis to investigate potential mediation of the association by healthcare service use.

RESULTS

Having had a hysterectomy was associated with an increased risk of thyroid cancer (odds ratio [OR] = 1.45, 95 % confidence interval [CI] 1.07-1.96). When stratified by indication for hysterectomy, the risk appeared stronger for those who had a hysterectomy for menstrual disorders (OR = 1.67, 95 % CI 1.17-2.37) but did not differ by tumour BRAF status. Approximately 20 % of the association between hysterectomy and thyroid cancer may be mediated by more frequent use of healthcare services.

CONCLUSIONS

The observed increased risk of thyroid cancer among those with hysterectomy may be driven, at least partly, by an altered sex steroid hormone milieu. More frequent healthcare service use by women with hysterectomy accounts for only a small proportion of the association.

Correction to 'Augmenting disease maps: a Bayesian meta-analysis approach'

[This corrects the article DOI: 10.1098/rsos.192151.][This corrects the article DOI: 10.1098/rsos.192151.].

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.

Hospital characteristics associated with better 'quality of surgery' and survival following oesophagogastric cancer surgery in Queensland: a population-level study

BACKGROUND

The impact of hospital characteristics on the quality of surgery and survival following oesophagogastric cancer surgery has not been well established in Australia. We assessed the interaction between hospital volume, service capability and surgical outcomes, with the hypothesis that both the quality of surgery and survival are better following treatment in high-volume, high service capability hospitals.

METHODS

All patients undergoing oesophagectomy and gastrectomy for cancer in Queensland, between 2001 and 2015, were included. Demographic, pathology and outcome data were collected. Hospitals were categorized into high (HV) (≥5 gastrectomies; ≥6 oesophagectomies) and low volume (LV). Hospital service capability was defined as high (HS) and low (LS), and then linked to hospital volume: HVHS, LVHS and LVLS. Higher quality surgery was defined using six perioperative parameters. Univariable comparisons of quality of surgery between hospital groups used chi-squared tests. The 5-year overall survival was compared using log-rank tests and Cox proportional hazard models.

RESULTS

For both gastrectomy and oesophagectomy, higher quality surgery occurred more frequently in HVHS hospitals (gastrectomy: HVHS = 44.2%, LVHS = 23.1%, LVLS = 29.1% (P < 0.01); oesophagectomy: HVHS = 34.5%, LVHS = 24.4%, LVLS = 21.7% (P = 0.01)). Following oesophagectomy, the 3- and 5-year overall survival was better following treatment in HVHS (P < 0.01). There was no difference between the groups following gastrectomy.

CONCLUSION

In Queensland, the quality of surgery was higher in HVHS hospitals performing gastrectomy and oesophagectomy; however, the impact on cancer survival was only seen following oesophagectomy.

Spatial and temporal variations in cervical cancer screening participation among indigenous and non-indigenous women, Queensland, Australia, 2008-2017

BACKGROUND

Cervical cancer incidence and mortality have declined in Australia since the implementation of a national cervical screening program in 1991, however, disparities in both measures between Indigenous and non-Indigenous women remain. We describe spatial and temporal changes in Pap test participation rates by Indigenous status for Queensland (Australia). Analyses were done in the context of renewed screening program in December 2017.

METHODS

Population-based study 2,132,925 Queensland female residents, aged 20-69 years who underwent cervical screening from 2008 to December 2017; 47,136 were identified as Indigenous through linkage to hospital records. Bayesian spatial models were used to generate smoothed estimates of participation across 528 small areas during 2008-2012 and 2013-2017 compared to the overall state average (2008-2017). Results are presented as thematic maps and graphs showing the associated uncertainty of the estimates.

RESULTS

Overall screening participation decreased over time for both Indigenous and non-Indigenous women. Strong spatial patterns were evident in five-year participation for both groups. Indigenous women had significantly lower participation than the Queensland average for ≥ 88 % of areas during both reporting periods whereas corresponding estimates were lower than average for <30 % of areas among non-Indigenous women. Disparities by Indigenous status persisted over time and remained across broader geographical groups of accessibility and area disadvantage.

CONCLUSIONS

Cervical cancer burden in Australia can only be reduced through concentrated efforts on identifying and addressing key drivers of the continuing disparities in screening participation. Achieving equitable screening participation for all women especially Indigenous women requires community engagement and localised interventions.

Multivariate Bayesian meta-analysis: joint modelling of multiple cancer types using summary statistics

BACKGROUND

Cancer atlases often provide estimates of cancer incidence, mortality or survival across small areas of a region or country. A recent example of a cancer atlas is the Australian cancer atlas (ACA), that provides interactive maps to visualise spatially smoothed estimates of cancer incidence and survival for 20 different cancer types over 2148 small areas across Australia.

METHODS

The present study proposes a multivariate Bayesian meta-analysis model, which can model multiple cancers jointly using summary measures without requiring access to the unit record data. This new approach is illustrated by modelling the publicly available spatially smoothed standardised incidence ratios for multiple cancers in the ACA divided into three groups: common, rare/less common and smoking-related. The multivariate Bayesian meta-analysis models are fitted to each group in order to explore any possible association between the cancers in three remoteness regions: major cities, regional and remote areas across Australia. The correlation between the pairs of cancers included in each multivariate model for a group was examined by computing the posterior correlation matrix for each cancer group in each region. The posterior correlation matrices in different remoteness regions were compared using Jennrich's test of equality of correlation matrices (Jennrich in J Am Stat Assoc. 1970;65(330):904-12. https://doi.org/10.1080/01621459.1970.10481133 ).

RESULTS

Substantive correlation was observed among some cancer types. There was evidence that the magnitude of this correlation varied according to remoteness of a region. For example, there has been significant negative correlation between prostate and lung cancer in major cities, but zero correlation found in regional and remote areas for the same pair of cancer types. High risk areas for specific combinations of cancer types were identified and visualised from the proposed model.

CONCLUSIONS

Publicly available spatially smoothed disease estimates can be used to explore additional research questions by modelling multiple cancer types jointly. These proposed multivariate meta-analysis models could be useful when unit record data are unavailable because of privacy and confidentiality requirements.

Multivariate Bayesian meta-analysis: joint modelling of multiple cancer types using summary statistics

BACKGROUND

Cancer atlases often provide estimates of cancer incidence, mortality or survival across small areas of a region or country. A recent example of a cancer atlas is the Australian cancer atlas (ACA), that provides interactive maps to visualise spatially smoothed estimates of cancer incidence and survival for 20 different cancer types over 2148 small areas across Australia.

METHODS

The present study proposes a multivariate Bayesian meta-analysis model, which can model multiple cancers jointly using summary measures without requiring access to the unit record data. This new approach is illustrated by modelling the publicly available spatially smoothed standardised incidence ratios for multiple cancers in the ACA divided into three groups: common, rare/less common and smoking-related. The multivariate Bayesian meta-analysis models are fitted to each group in order to explore any possible association between the cancers in three remoteness regions: major cities, regional and remote areas across Australia. The correlation between the pairs of cancers included in each multivariate model for a group was examined by computing the posterior correlation matrix for each cancer group in each region. The posterior correlation matrices in different remoteness regions were compared using Jennrich's test of equality of correlation matrices (Jennrich in J Am Stat Assoc. 1970;65(330):904-12. https://doi.org/10.1080/01621459.1970.10481133 ).

RESULTS

Substantive correlation was observed among some cancer types. There was evidence that the magnitude of this correlation varied according to remoteness of a region. For example, there has been significant negative correlation between prostate and lung cancer in major cities, but zero correlation found in regional and remote areas for the same pair of cancer types. High risk areas for specific combinations of cancer types were identified and visualised from the proposed model.

CONCLUSIONS

Publicly available spatially smoothed disease estimates can be used to explore additional research questions by modelling multiple cancer types jointly. These proposed multivariate meta-analysis models could be useful when unit record data are unavailable because of privacy and confidentiality requirements.

Obesity Is Associated with BRAFV600E-Mutated Thyroid Cancer

Background: Thyroid cancer incidence has increased in many parts of the world since the 1980s, as has the prevalence of obesity. Evidence suggests that people with greater body size have higher thyroid cancer risk. However, it is unclear whether this association is causal or is driven by over-diagnosis of indolent cancers, because overweight/obese people use health services more frequently than those of normal weight, thus conferring greater opportunity for incidental diagnosis. Assessing whether obesity is associated with higher-risk thyroid cancers might help clarify this issue. Methods: We recruited 1013 people diagnosed with thyroid cancer between 2013 and 2016 and 1057 population controls, frequency matched by sex and age group. We used logistic regression to assess the association between body mass index (BMI) and overall thyroid cancer risk as well as by tumor BRAF mutational status as a marker of potentially higher-risk cancer. Results: Overall, obesity was associated with greater risk of thyroid cancer (odds ratio [OR] = 1.72; 95% confidence interval [CI 1.37-2.16] for obese vs. normal BMI). The association with obesity was significantly stronger for BRAF-mutation positive than BRAF-negative papillary thyroid cancers (PTCs; OR = 1.71 [CI 1.17-2.50] for BRAF-positive vs. BRAF-negative cancers). The increased risks associated with overweight/obesity did not vary by histological subtypes or presence/absence of adverse tumor histologic features. Conclusions: Greater risk of BRAF-mutated PTCs among those with high BMI suggests that the association may not merely reflect greater health care service use and indicates an independent relationship between obesity and clinically important thyroid cancer.

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.

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.

Pancreaticoduodenectomy in a low-resection volume region: a population-level study examining the impact of hospital-volume on surgical quality and longer-term survival

BACKGROUND

An association between higher hospital-volume and better "quality of surgery" and long-term survival has not been reported following pancreatic cancer surgery in low resection-volume regions such as in Australia. Using a population-level study, we compare "quality of surgery" and two-year survival following pancreaticoduodenectomy between Australian hospitals grouped by resection-volume.

METHODS

Data on all patients undergoing pancreaticoduodenectomy for adenocarcinoma in the Australian state of Queensland, between 2001 and 2015, were obtained from the Queensland Oncology Repository. Hospitals were grouped into high (≥6 resections annually) and low (<6) volume centres. Following adjustment for case-mix, "quality-of-treatment" indicators were compared between hospital groups using multivariate logistic regression and Poisson regression analysis; and two-year cancer-specific and overall survival were compared using multivariate Cox proportional hazard models.

RESULTS

Compared with high-volume centres, low-volume centres had worse two-year cancer-specific survival (Adjusted HR = 1.31; 95% CI:1.03-1.68), higher 30-day mortality (Adjusted IRR = 3.81; 95% CI: 1.36-10.62) and fewer patients received "high-quality surgery" (Adjusted OR = 0.55; 95% CI: 0.33-0.90). Differences in 30-day mortality, or "quality-of-treatment" indicators did not entirely explain the observed survival difference between hospital-volume groups.

CONCLUSION

In an Australian environment, a "high" hospital-volume was significantly associated with better quality surgery and two-year survival following pancreaticoduodenectomy.

Augmenting disease maps: a Bayesian meta-analysis approach

Analysis of spatial patterns of disease is a significant field of research. However, access to unit-level disease data can be difficult for privacy and other reasons. As a consequence, estimates of interest are often published at the small area level as disease maps. This motivates the development of methods for analysis of these ecological estimates directly. Such analyses can widen the scope of research by drawing more insights from published disease maps or atlases. The present study proposes a hierarchical Bayesian meta-analysis model that analyses the point and interval estimates from an online atlas. The proposed model is illustrated by modelling the published cancer incidence estimates available as part of the online Australian Cancer Atlas (ACA). The proposed model aims to reveal patterns of cancer incidence for the 20 cancers included in ACA in major cities, regional and remote areas. The model results are validated using the observed areal data created from unit-level data on cancer incidence in each of 2148 small areas. It is found that the meta-analysis models can generate similar patterns of cancer incidence based on urban/rural status of small areas compared with those already known or revealed by the analysis of observed data. The proposed approach can be generalized to other online disease maps and atlases.

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.

Long-term deaths from melanoma according to tumor thickness at diagnosis

There is little long-term follow-up information about how the number of melanoma deaths and case fatality vary over time according to the measured thickness of melanoma at diagnosis. This population-based longitudinal cohort study examines patterns and trends in case fatality among 44,531 people in Queensland (Australia) diagnosed with a single invasive melanoma (International Classification of Diseases for Oncology, third revision [ICD-O-3], C44, Morphology 872-879) between 1987 and 2011, including 11,883 diagnosed between 1987 and 1996, with up to 20 years follow-up (to December 2016). The 20-year case fatality increased by thickness, with the percentage of melanoma deaths within 20 years of diagnosis being up to 4.8% for melanomas with measured thickness <0.80 mm, 10.6% for tumors 0.8 to <1.0 mm and generally more than 30% for melanomas measuring 3 mm and more. For melanomas <1.0 mm, most deaths occurred between 5 and 20 years after diagnosis, whereas for thicker melanomas the reverse was true with most deaths occurring within the first 5 years. Five-year case fatality decreased over successive calendar time periods for melanomas <1.0 mm, but not for melanomas ≥1.0 mm. These findings demonstrate that the time course for fatal melanomas varies markedly according to tumor thickness at diagnosis. Improved understanding of the patient factors and characteristics of melanomas, in addition to tumor thickness, which increase the likelihood of progression, is needed to guide clinical diagnosis, communication with patients and ongoing surveillance pathways of patients with potentially fatal lesions.

Global Trends in Incidence Rates of Primary Adult Liver Cancers: A Systematic Review and Meta-Analysis

Background: Primary liver cancer is a leading cause of cancer deaths worldwide. Global burden varies, reflecting geographical distribution of viral hepatitis. Our objective was to perform a systematic review and meta-analysis of published current trends in incidence of adult liver cancers and histological types worldwide.

Methods: This study used systematic searches of PubMed, Embase, CINAHL, and Web of Science databases for English-language peer-reviewed articles published from 1 January 2008 to 01 September 2019. Inclusion criteria were population-based studies of adult liver cancer patients with quantitative estimates of temporal trends in incidence for liver cancers and/or histological types. For multiple studies from the same geographical area, only the publication that reported the most recent trends for the same cancer type and population subgroup was included. Review was conducted per PRISMA guidelines. Two authors independently extracted data and critically assessed studies. Proposed contributors to observed trends were extracted from included articles. Study-specific estimates of the annual percentage change (APC) in incidence rates with 95% confidence intervals (CIs) were pooled using random-effects meta-analysis models. Heterogeneity was measured using the I² statistics and publication bias evaluated using funnel plots and Egger's tests.

Results: Overall, 53 studies met the inclusion criteria, of which 31 were included in the meta-analysis. Overall, pooled APC estimates were +0.8 (95% CI −0.3, +2.0) for liver cancers combined, +2.6 (95% CI +1.2, +4.0) for hepatocellular carcinoma (HCC), and +4.3 (95% CI +2.5, +6.1) for intrahepatic cholangiocarcinoma. Subgroup analyses indicated increasing trends for liver cancers (APC +3.2, 95% CI +2.5, +3.9) and HCC (APC +3.6, 95% CI +2.9, +4.4) in the region of North America/Europe/Australia, whereas corresponding trends were decreasing (APC −1.7, 95% CI −2.2, −1.1) and stable (APC −0.7, 95% CI −1.9, +0.5) in Asia, respectively.

Conclusions: Incidence is increasing for adult liver cancers and HCC in Western countries, whereas trends are decreasing in the Asian region, although still remaining high. Our findings highlight the importance of viral hepatitis control and lifestyle interventions to reduce global liver cancer burden. Ongoing surveillance is also vital to detect early shifts in incidence trends.

The incidence of childhood cancer in Australia, 1983-2015, and projections to 2035

Objectives

To describe changes in childhood cancer incidence in Australia, 1983–2015, and to estimate projected incidence to 2035.

Design, setting

Population‐based study; analysis of Australian Childhood Cancer Registry data for the 20 547 children under 15 years of age diagnosed with cancer in Australia between 1983 and 2015.

Main outcome measures

Incidence rate changes during 1983–2015 were assessed by joinpoint regression, with rates age‐standardised to the 2001 Australian standard population. Incidence projections to 2035 were estimated by age‐period‐cohort modelling.

Results

The overall age‐standardised incidence rate of childhood cancer increased by 34% between 1983 and 2015, increasing by 1.2% (95% CI, +0.5% to +1.9%) per annum between 2005 and 2015. During 2011–2015, the mean annual number of children diagnosed with cancer in Australia was 770, an incidence rate of 174 cases (95% CI, 169–180 cases) per million children per year. The incidence of hepatoblastoma (annual percentage change [APC], +2.3%; 95% CI, +0.8% to +3.8%), Burkitt lymphoma (APC, +1.6%; 95% CI, +0.4% to +2.8%), osteosarcoma (APC, +1.1%; 95%, +0.0% to +2.3%), intracranial and intraspinal embryonal tumours (APC, +0.9%; 95% CI, +0.4% to +1.5%), and lymphoid leukaemia (APC, +0.5%; 95% CI, +0.2% to +0.8%) increased significantly across the period 1983–2015. The incidence rate of childhood melanoma fell sharply between 1996 and 2015 (APC, –7.7%; 95% CI, –10% to –4.8%). The overall annual cancer incidence rate is conservatively projected to rise to about 186 cases (95% CI, 175–197 cases) per million children by 2035 (1060 cases per year).

Conclusions

The incidence rates of several childhood cancer types steadily increased during 1983–2015. Although the reasons for these rises are largely unknown, our findings provide a foundation for health service planning for meeting the needs of children who will be diagnosed with cancer until 2035.

The impact of reducing alcohol consumption in Australia: An estimate of the proportion of potentially avoidable cancers 2013-2037

The International Agency for Research on Cancer first concluded that alcohol causes cancer in humans in 1988. The World Cancer Research Fund has declared that alcohol causes cancer of the oral cavity, pharynx, larynx, oesophagus (squamous cell carcinoma), female breast, colon, rectum, stomach and liver. It recommended that alcohol be avoided altogether to prevent cancer. We aimed to quantify the impact of reducing alcohol consumption on future cancer incidence in Australia. We used PREVENT 3.01 simulation modelling software to estimate the proportion of cancers that could potentially be prevented over a 25-year period under two hypothetical intervention scenarios and two latency periods (20 and 30 years). Under a scenario where alcohol consumption abruptly ceases, we estimated up to 4% of alcohol-related cancers could be avoided over a 25-year period (~49,500 cancers, depending on assumed latency). If the maximum consumption of all Australian adults was ≤20 g/day (~two Australian standard drinks), up to 2% of alcohol-related cancers could be avoided (~29,600 cancers). The maximum proportions were higher for men (6% for no alcohol consumption; 5% for ≤20 g/day) than women (3%; 1%). The proportion avoidable was highest for oesophageal squamous cell carcinoma (17% no alcohol consumption; 9% ≤20 g/day), followed by cancers of the oral cavity (12%; 5%) and pharynx (11%; 5%). The cancer sites with the highest numbers of potentially avoidable cases were colon in men (11,500; 9,900) and breast in women (14,400; 4,100). Successful interventions to reduce alcohol intake could lead to significant reductions in cancer incidence.

Second primary cancers in people who had cancer as children: an Australian Childhood Cancer Registry population-based study

OBJECTIVE

To investigate the incidence of second primary cancers in people diagnosed with cancer during childhood.

DESIGN, SETTING

Retrospective, population-based study; analysis of Australian Childhood Cancer Registry data.

PARTICIPANTS

People alive at least two months after being diagnosed before the age of 15 years with a primary cancer, 1983-2013, followed until 31 December 2015 (2-33 years' follow-up).

MAIN OUTCOME MEASURES

Risks of second primary cancer compared with the general population, expressed as standardised incidence ratios (SIRs).

RESULTS

Among 18 230 people diagnosed with cancer during childhood, 388 (2%) were later diagnosed with second primary cancers; the estimated 30-year cumulative incidence of second cancers was 4.4% (95% CI, 3.8-5.0%). The risk of a new primary cancer was five times as high as for the general population (SIR, 5.13; 95% CI, 4.65-5.67). Relative risk of a second primary cancer was greatest for people who had childhood rhabdomyosarcoma (SIR, 19.9; 95% CI, 14.4-27.6). Relative risk was particularly high for children who had undergone both chemotherapy and radiotherapy (SIR, 9.80; 95% CI, 8.35-11.5). Relative risk peaked during the 5 years following the first diagnosis (2 to less than 5 years: SIR, 10.3; 95% CI, 8.20-13.0), but was still significant at 20-33 years (SIR, 2.58; 95% CI, 2.02-3.30). The most frequent second primary cancers were thyroid carcinomas (65 of 388, 17%) and acute myeloid leukaemias (57, 15%).

CONCLUSIONS

Survivors of childhood cancer remain at increased risk of a second primary cancer well into adulthood. As the late effects of cancer treatment probably contribute to this risk, treatments need to be refined and their toxicity reduced, without reducing their benefit for survival.

Development of the Australian Cancer Atlas: spatial modelling, visualisation, and reporting of estimates

BACKGROUND

It is well known that the burden caused by cancer can vary geographically, which may relate to differences in health, economics or lifestyle. However, to date, there was no comprehensive picture of how the cancer burden, measured by cancer incidence and survival, varied by small geographical area across Australia.

METHODS

The Atlas consists of 2148 Statistical Areas level 2 across Australia defined by the Australian Statistical Geography Standard which provide the best compromise between small population and small area. Cancer burden was estimated for males, females, and persons separately, with 50 unique sex-specific (males, females, all persons) cancer types analysed. Incidence and relative survival were modelled with Bayesian spatial models using the Leroux prior which was carefully selected to provide adequate spatial smoothing while reflecting genuine geographic variation. Markov Chain Monte Carlo estimation was used because it facilitates quantifying the uncertainty of the posterior estimates numerically and visually.

RESULTS

The results of the statistical model and visualisation development were published through the release of the Australian Cancer Atlas ( https://atlas.cancer.org.au ) in September, 2018. The Australian Cancer Atlas provides the first freely available, digital, interactive picture of cancer incidence and survival at the small geographical level across Australia with a focus on incorporating uncertainty, while also providing the tools necessary for accurate estimation and appropriate interpretation and decision making.

CONCLUSIONS

The success of the Atlas will be measured by how widely it is used by key stakeholders to guide research and inform decision making. It is hoped that the Atlas and the methodology behind it motivates new research opportunities that lead to improvements in our understanding of the geographical patterns of cancer burden, possible causes or risk factors, and the reasons for differences in variation between cancer types, both within Australia and globally. Future versions of the Atlas are planned to include new data sources to include indicators such as cancer screening and treatment, and extensions to the statistical methods to incorporate changes in geographical patterns over time.

Service Level Factors Associated with Cervical Screening in Aboriginal and Torres Strait Islander Primary Health Care Centres in Australia

Aboriginal and Torres Strait Islander women have significantly higher cervical cancer incidence and mortality than other Australian women. In this study, we assessed the documented delivery of cervical screening for women attending Indigenous Primary Health Care (PHC) centres across Australia and identified service-level factors associated with between-centre variation in screening coverage. We analysed 3801 clinical audit records for PHC clients aged 20–64 years from 135 Indigenous PHC centres participating in the Audit for Best Practice in Chronic Disease (ABCD) continuous quality improvement (CQI) program across five Australian states/territories during 2005 to 2014. Multilevel logistic regression models were used to identify service-level factors associated with screening, while accounting for differences in client-level factors. There was substantial variation in the proportion of clients who had a documented cervical screen in the previous two years across the participating PHC centres (median 50%, interquartile range (IQR): 29–67%), persisting over years and audit cycle. Centre-level factors explained 40% of the variation; client-level factors did not reduce the between-centre variation. Screening coverage was associated with longer time enrolled in the CQI program and very remote location. Indigenous PHC centres play an important role in providing cervical screening to Aboriginal and Torres Strait Islander women. Thus, their leadership is essential to ensure that Australia’s public health commitment to the elimination of cervical cancer includes Aboriginal and Torres Strait Islander women. A sustained commitment to CQI may improve PHC centres delivery of cervical screening; however, factors that may impact on service delivery, such as organisational, geographical and environmental factors, warrant further investigation.