Impact of geographic area level on measuring socioeconomic disparities in cancer survival in New South Wales,Australia: A period analysis

BackgroundArea-based socioeconomic measures are widely used in health research. In theory, the larger the area used the more individual misclassification is introduced, thus biasing the association between such area level measures and health outcomes. In this study, we examined the socioeconomic disparities in cancer survival using two geographic area-based measures to see if the size of the area matters.MethodsWe used population-based cancer registry data for patients diagnosed with one of 10 major cancers in New South Wales (NSW), Australia during 2004–2008. Patients were assigned index measures of socioeconomic status (SES) based on two area-level units, census Collection District (CD) and Local Government Area (LGA) of their address at diagnosis. Five-year relative survival was estimated using the period approach for patients alive during 2004–2008, for each socioeconomic quintile at each area-level for each cancer. Poisson-regression modelling was used to adjust for socioeconomic quintile, sex, age-group at diagnosis and disease stage at diagnosis. The relative excess risk of death (RER) by socioeconomic quintile derived from this modelling was compared between area-units.ResultsWe found extensive disagreement in SES classification between CD and LGA levels across all socioeconomic quintiles, particularly for more disadvantaged groups. In general, more disadvantaged patients had significantly lower survival than the least disadvantaged group for both CD and LGA classifications. The socioeconomic survival disparities detected by CD classification were larger than those detected by LGA. Adjusted RER estimates by SES were similar for most cancers when measured at both area levels.ConclusionsWe found that classifying patient SES by the widely used Australian geographic unit LGA results in underestimation of survival disparities for several cancers compared to when SES is classified at the geographically smaller CD level. Despite this, our RER of death estimates derived from these survival estimates were generally similar for both CD and LGA level analyses, suggesting that LGAs remain a valuable spatial unit for use in Australian health and social research, though the potential for misclassification must be considered when interpreting research. While data confidentiality concerns increase with the level of geographical precision, the use of smaller area-level health and census data in the future, with appropriate allowance for confidentiality     

Disparities in survival of stomach cancer among different socioeconomic groups in North-East Netherlands

Background: Survival differences in stomach cancer are depended on patient, tumour and treatment factors. Some populations are more prone to develop stomach cancer, such as people with low socioeconomic status (SES). The aim of this population based study was to assess whether differences in socioeconomic status (SES) alone, after adjusting for confounding factors, also influence survival. Methods: From 1989 to 2007 all patients with stomach cancer were selected from the cancer registry of the Comprehensive Cancer Centre North-East. Postal code at diagnosis was used to determine SES, dividing patients in three groups; low, intermediate and high SES. Associations between age, localization, grade, stage, and treatment were determined using Chi-square analysis. Relative survival analysis was used to estimate relative excess risk (RER) of dying according to SES. Results: In low SES neighbourhoods diagnosis was established at older age. More distal tumours were detected in patients with low SES, whereas pathology showed more poorly differentiated tumours in patients with high SES. Overall, more resections were performed in, and more chemotherapy was administrated to patients in high SES neighbourhoods. After adjusting for confounding factors, the risk of dying was lower for patients with high SES (RER 0.89, 95% Confidence Interval 0.81–0.98) compared to patients with low SES. Conclusion: SES proved to be an independent prognostic factor for survival in patients with stomach cancer.     

Progress in cancer survival across last two decades: A nationwide study of over 1.2 million Polish patients diagnosed with the most common cancers

BackgroundThe purpose of this study was to estimate the high incidence cancers survival in Poland between 2000 and 2018, with the following aim to monitor the national polish cancer control program 2020–2030 effectiveness. We calculated survival in cancer of lung, breast, prostate, colon, rectum, ovarian, cervical cancers, and skin melanoma.MethodsData were obtained from the Polish Cancer Registry (PLCR). We estimated age-standardized 5-year net survival (NS) with the life table method and the Pohar-Perme estimator using the International Cancer Survival Standard weights. The corresponding 95% confidence intervals (95% CI) were estimated with log transformation.ResultsOverall, 1,288,944 high incidence cancer cases were included in the study (622,486 men and 666,458 women). In 2015–2018 age-standardized 5-year NS was 85.2% (95% CI = 84.6% to 85.8%) in prostate cancer, 80.0% (79.5% to 80.4%) breast cancer, 77.3%(76.4% to 78.1%) melanoma, 58.5% (57.5% to 59.5%) cervical cancer, 57.9% (57.3% to 58.5%) colon cancer, 52.1% (51.3% to 52.9%) rectal cancer, 43.3% (42.4% to 44.3%) ovarian cancer, and 17.8% (17.4% to 18.1%) for lung cancer. Between the 2000–2004 and 2015–2018 the highest increase in survival was noted for prostate cancer (14.6% points [pp]; from 70.6% to 85.2%) and the lowest for lung cancer (4.5 pp; from 13.3% to 17.8%).ConclusionCancer survivorship has been consistently improving during the last two decades. Notwithstanding these overall encouraging results, more extraordinary efforts are needed to close the cancer survival gap in Poland.     

Regional disparities in cancer survival in Iran: Insight from a National Surveillance of Cancer Survival in Iran (IRANCANSURV)

Background and objectivesWe aimed to investigate geographical disparity in cancer survival in 9 provincial population-based cancer registries in Iran from 2015 to 2016.Material and methodIn the current study, data from 90,862 adult patients (aged >15 years) diagnosed with cancer were retrieved from 9 population-based cancer registries across Iran. Five-year survival rates were estimated by applying relative survival approaches. We also applied the international cancer survival standard weights for age standardization. Finally, we calculated the excess hazard ratio (EHR) for each province adjusted for age, sex, and cancer sites to estimate the excess hazard ratio of mortality compared to the capital province (Tehran).ResultsThe largest gap in survival was observed in more curable cancer types, including melanoma (41.4%), ovary (32.3%), cervix (35.0%), prostate (26.7%), and rectum (21.4%), while the observed geographical disparity in lethal cancers such as lung, brain, stomach, and pancreas was less than 15%. Compared to Tehran, we found the highest excess hazard of death in Western Azerbaijan (EHR=1.60, 95% CI 1.51, 1.65), Kermanshah (EHR=1.52, 95% CI=1.44, 1.61), and Kerman (EHR=1.46, 95% CI=1.38, 1.53). The hazard ratio of death was almost identical in Isfahan (EHR=1.04, 95% CI=1.03, 1.06) and Tehran provinces.ConclusionProvinces with higher HDI had better survival rates. IRANCANSURV study showed regional disparities in cancer survival in Iran. Cancer patients in provinces with a higher Human Development Index (HDI) had a higher survival rate and lived longer compared to the patients in provinces with medium and low HDI regions.     

Partner status and survival after cancer: A competing risks analysis

ObjectiveThe survival benefits of having a partner for all cancers combined is well recognized, however its prognostic importance for individual cancer types, including competing mortality causes, is less clear. This study was undertaken to quantify the impact of partner status on survival due to cancer-specific and competing mortality causes.MethodsData were obtained from the population-based Queensland Cancer Registry on 176,050 incident cases of ten leading cancers diagnosed in Queensland (Australia) from 1996 to 2012. Flexible parametric competing-risks models were used to estimate cause-specific hazards and cumulative probabilities of death, adjusting for age, stage (breast, colorectal and melanoma only) and stratifying by sex.ResultsBoth unpartnered males and females had higher total cumulative probability of death than their partnered counterparts for each site. For example, the survival disadvantage for unpartnered males ranged from 3% to 30% with higher mortality burden from both the primary cancer and competing mortality causes. The cause-specific age-adjusted hazard ratios were also consistent with patients without a partner having increased mortality risk although the specific effect varied by site, sex and cause of death. For all combined sites, unpartnered males had a 46%, 18% and 44% higher risk of cancer-specific, other cancer and non-cancer mortality respectively with similar patterns for females. The higher mortality risk persisted after adjustment for stage.ConclusionsIt is important to better understand the mechanisms by which having a partner is beneficial following a cancer diagnosis, so that this can inform improvements in cancer management for all people with cancer.     

Ethnic,racial and socioeconomic disparities in breast cancer survival in two Brazilian capitals between 1996 and 2012

ObjectiveTo study the impact of socio-economic status and ethno-racial strata on excess mortality hazard and net survival of women with breast cancer in two Brazilian state capitals.MethodWe conducted a survival analysis with individual data from population-based cancer registries including women with breast cancer diagnosed between 1996 and 2012 in Aracaju and Curitiba. The main outcomes were the excess mortality hazard (EMH) and net survival. The associations of age, year of diagnosis, disease stage, race/skin colour and socioeconomic status (SES) with the excess mortality hazard and net survival were analysed using multi-level spline regression models, modelled as cubic splines with knots at 1 and 5 years of follow-up.ResultsA total of 2045 women in Aracaju and 7872 in Curitiba were included in the analyses. The EMH was higher for women with lower SES and for black and brown women in both municipalities. The greatest difference in excess mortality was seen between the most deprived women and the most affluent women in Curitiba, hazard ratio (HR) 1.93 (95%CI 1.63–2.28). For race/skin colour, the greatest ratio was found in Curitiba (HR 1.35, 95%CI 1.09–1.66) for black women compared with white women. The most important socio-economic difference in net survival was seen in Aracaju. Age-standardised net survival at five years was 55.7% for the most deprived women and 67.2% for the most affluent. Net survival at eight years was 48.3% and 61.0%, respectively. Net survival in Curitiba was higher than in Aracaju in all SES groups.”ConclusionOur findings suggest the presence of contrasting breast cancer survival expectancy in Aracaju and Curitiba, highlighting regional inequalities in access to health care. Lower survival among brown and black women, and those in lower SES groups indicates that early detection, early diagnosis and timely access to treatment must be prioritized to reduce inequalities in outcome among Brazilian women.     

Racial disparities in treatment and survival from ovarian cancer

BackgroundBlack women with ovarian cancer in the U.S. have lower survival than whites. We aimed to identify factors associated with racial differences in ovarian cancer treatment and overall survival (OS).MethodsWe examined data from 365 white and 95 black ovarian cancer patients from the Hollings Cancer Center Cancer Registry in Charleston, S.C. between 2000 and 2015. We used unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between race and receipt of surgery and chemotherapy, and Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% CIs between race and OS. Model variables included diagnosis center, stage, histology, insurance status, smoking, age-adjusted Charlson comorbidity index (AACI) and residual disease. Interactions between race and AACI were assessed using −2 log likelihood tests.ResultsBlacks vs. whites were over two-fold less likely to receive a surgery-chemotherapy sequence (multivariable-adjusted OR 2.46, 95% CI 1.43–4.21), particularly if they had a higher AACI (interaction p = 0.008). In multivariable-adjusted Cox models, black women were at higher risk of death (HR 1.81, 95% CI 1.35–2.43) than whites, even when restricted to patients who received a surgery-chemotherapy sequence (HR 1.79, 95% CI 1.10–2.89) and particularly for those with higher AACI (HR 4.70, 95% CI 2.00 − 11.02, interaction p = 0.01).ConclusionsAmong blacks, higher comorbidity associates with less chance of receiving guideline-based treatment and also modifies OS. Differences in receipt of guideline-based care do not completely explain survival differences between blacks and whites with ovarian cancer. These results highlight opportunities for further research.     

Variation in the relationship between BMI and survival by socioeconomic status in Great Britain

We investigate the relationship between obesity and survival, and the extent to which this relationship varies by socioeconomic status (SES). The underlying model is based on the “Pathways to health” framework in which SES affects health by modifying the relationship between lifestyles and health. We use data from the British Health and Lifestyle Survey (1984–1985) and the longitudinal follow-up in June 2009, and run parametric Gompertz survival models to investigate the association between obesity and survival, also accounting for interactions between obesity and both age and SES. Generally we find that obesity is negatively associated with survival, and that SES is positively associated with survival, in both men and women. The interactions between obesity and SES predict survival among women but not among men. Obesity compared with normal weight is associated with a reduction in survival of 3.3, 3.2 and 2.8 years in men aged 40, 50 and 60 years, respectively. Corresponding numbers among women in the lowest SES group are 13.1, 9.7 and 6.1 years, respectively; in the highest SES group they are 6.2, 3.1 and 0.1 years, respectively, a difference of approximately 6 years between the highest and lowest SES groups.     

Unstaged cancer in a population-based registry: Prevalence,predictors and patient prognosis

Purpose: Information on cancer stage at diagnosis is critical for population studies investigating cancer care and outcomes. Few studies have examined the factors which impact (1) staging or (2) outcomes for patients who are registered as having unknown stage. This study investigated (1) the prevalence of unknown stage at diagnosis on the New Zealand Cancer Registry (NZCR); (2) explored factors which predict unknown stage; (3) described receipt of surgery and (4) survival outcomes for patients with unknown stage. Methods: Patients diagnosed with the most prevalent 18 cancers between 2006 and 2008 (N = 41,489) were identified from the NZCR, with additional data obtained from mortality and hospitalisation databases. Logistic and Cox regression were used to investigate predictors of unknown stage and patient outcomes. Results: (1) Three distinct groups of cancers were found based on proportion of patients with unknown stage (low = up to 33% unknown stage; moderate = 33–64%; high = 65%+). (2) Increasing age was a significant predictor of unknown stage (adjusted odds ratios [ORs]: 1.18–1.24 per 5-year increase across groups). Patients with substantive comorbidity were more likely to have unknown stage but only for those cancers with a low (OR = 2.65 [2.28–3.09]) or moderate (OR = 1.17 [1.03–1.33]) proportion of patients with unknown stage. (3) Patients with unknown stage were significantly less likely to have received definitive surgery than those with local or regional disease across investigated cancers. (4) Patients with unknown stage had 28-day and 1-year survival which was intermediate between regional and distant disease. Discussion: We found that stage completeness differs widely by cancer site. In many cases, the proportion of unknown stage on a population-based register can be explained by patient, service and/or cancer related factors.     

Probabilities of dying from cancer and other causes in French cancer patients based on an unbiased estimator of net survival: A study of five common cancers

BackgroundNet survival is the survival that would be observed if cancer were the only possible cause of death. Although it is an important epidemiological tool allowing temporal or geographical comparisons, it cannot inform on the “crude” probability of death of cancer patients; i.e., when taking into account other possible causes of deaths.MethodsIn this work, we provide estimates of the crude probabilities of death from cancer and from other causes as well as the probability of being alive up to ten years after cancer diagnosis according to the age and year of diagnosis. Based on a flexible excess hazard model providing unbiased estimates of net survival, our methodology avoids the pitfalls associated with the use of the cause of death. We used data from FRANCIM, the French network of cancer registries, and studied five common cancer sites: head and neck, breast, prostate, lung, and colorectal cancers.ResultsFor breast, prostate, and colorectal cancers, the impact of the other causes on the total probability of death increased with the age at diagnosis whereas it remained negligible for lung and head and neck cancers whatever the age. For breast, prostate, and colorectal cancer, the more recently was the cancer diagnosed, the less was the probability of death from cancer.ConclusionThe crude probability of death is an intuitive concept that may prove particularly useful in choosing an appropriate treatment, or refining the indication of a screening strategy by allowing the clinician to estimate the proportion of cancer patients who will die specifically from cancer.     

Increased incidence of rare cancers and varied age distributions by cancer group: A population-based cancer registry study in Hiroshima Prefecture,Japan

BackgroundEpidemiological characteristics of many types of rare cancers are limited especially in Asia. Therefore, this study aimed to describe the burden and changing time trends of rare cancers in Hiroshima, Japan.MethodsThe internationally agreed RARECAREnet list of rare cancers was used to identify patients diagnosed with cancers from 2005 to 2015 who were registered in the Hiroshima Prefecture Cancer Registry. Quality indicators specific to rare cancers were assessed by cancer grouping. Crude incidence rates (IRs) and age-standardized rates (ASRs) were calculated for 216 single cancers (rare and common) included in the list. A joinpoint regression was used to analyze age distribution and time trends in the ASRs for 12 internationally agreed rare cancer families. Quality indicators, ASRs, and IRs in Japan were identified to examine IR differences and the effects on data accuracy.ResultsThe 231,328 cases were used to calculate the IRs of each cancer. Epithelial tumors in rare families increased with age, but nonepithelial tumors occurred at any age. The proportion of rare cancer families to total cancers was stable. The time trend for families of head and neck cancers (annual percent change and 95 % confidence interval: 2.4 %; 1.2–3.7 %), neuroendocrine tumors (6.6 %; 5.1–8.1 %), and hematological cancers (4.3 %; 3.2–5.5 %) markedly increased.ConclusionThe ASRs of several rare cancers increased because of increased knowledge of these diseases, improved diagnostic techniques, and aggressive diagnoses.     

Effects of the length of central cancer registry operations on identification of subsequent cancers and on survival estimates

BackgroundPopulation-based cancer survival analyses have traditionally been based on the first primary cancer. Recent studies have brought this practice into question, arguing that varying registry reference dates affect the ability to identify earlier cancers, resulting in selection bias. We used a theoretical approach to evaluate the extent to which the length of registry operations affects the classification of first versus subsequent cancers and consequently survival estimates.MethodsSequence number central was used to classify tumors from the New York State Cancer Registry, diagnosed 2001–2010, as either first primaries (value = 0 or 1) or subsequent primaries (≥2). A set of three sequence numbers, each based on an assumed reference year (1976, 1986 or 1996), was assigned to each tumor. Percent of subsequent cancers was evaluated by reference year, cancer site and age. 5-year relative survival estimates were compared under four different selection scenarios.ResultsThe percent of cancer cases classified as subsequent primaries was 15.3%, 14.3% and 11.2% for reference years 1976, 1986 and 1996, respectively; and varied by cancer site and age. When only the first primary was included, shorter registry operation time was associated with slightly lower 5-year survival estimates. When all primary cancers were included, survival estimates decreased, with the largest decreases seen for the earliest reference year.ConclusionsRegistry operation length affected the identification of subsequent cancers, but the overall effect of this misclassification on survival estimates was small. Survival estimates based on all primary cancers were slightly lower, but might be more comparable across registries.     

Characteristics of cases with unknown stage prostate cancer in a population-based cancer registry

BackgroundThe New South Wales Central Cancer Registry (NSW CCR) is the only population-based cancer registry in Australia that has routinely collected summary stage at diagnosis since its inception in 1972. However, a large proportion of prostate cancer cases have “unknown” stage recorded by the registry. We investigated the characteristics of prostate cancer cases with “unknown” stage recorded by the NSW CCR, and examined survival for this group.MethodsData were obtained from the NSW CCR for all first primary prostate cancer cases diagnosed in 1999–2007. Summary stage was recorded as localised, regional, distant or “unknown”. Associations between disease stage and patient characteristics (age, place of residence at diagnosis, year of diagnosis and country of birth) and prostate cancer specific survival were investigated using multivariable logistic regression and Cox proportional hazards models respectively.ResultsOf 39 852 prostate cancer cases, 41.8% had “unknown” stage recorded by the NSW CCR. This proportion decreased significantly over time, increased with increasing age at diagnosis and was higher for those living in socio-economically disadvantaged areas. The proportion with “unknown” stage varied across area health services. Prostate cancer specific survival for cases with “unknown” stage was significantly poorer than for those with localised stage but better than for those with regional or distant stage.ConclusionsResearchers or others using cancer registry stage data to examine prostate cancer outcomes need to consider the differences between cases with “unknown” stage at diagnosis and those with known stage recorded by the registry, and what impact this may have on their results.     

Control of data quality for population-based cancer survival analysis

BackgroundPopulation-based cancer survival is an important measure of the overall effectiveness of cancer care in a population. Population-based cancer registries collect data that enable the estimation of cancer survival. To ensure accurate, consistent and comparable survival estimates, strict control of data quality is required before the survival analyses are carried out. In this paper, we present a basis for data quality control for cancer survival.MethodsWe propose three distinct phases for the quality control. Firstly, each individual variable within a given record is examined to identify departures from the study protocol; secondly, each record is checked and excluded if it is ineligible or logically incoherent for analysis; lastly, the distributions of key characteristics in the whole dataset are examined for their plausibility.ResultsData for patients diagnosed with bladder cancer in England between 1991 and 2010 are used as an example to aid the interpretation of the differences in data quality. The effect of different aspects of data quality on survival estimates is discussed.ConclusionsWe recommend that the results of data quality procedures should be reported together with the findings from survival analysis, to facilitate their interpretation.     

The impact of health insurance affiliation and socioeconomic status on cervical cancer survival in Bucaramanga,Colombia

Cervical cancer is still an important cause of death in countries like Colombia. We aimed to determine whether socioeconomic status of residential address (SES) and type of health insurance affiliation (HIA) might be associated with cervical cancer survival among women in Bucaramanga, Colombia. All patients residing in the Bucaramanga Metropolitan Area diagnosed with invasive cervical cancer (ICD-0–3 codes C53.X) between 2008 and 2016 (n = 725) were identified through the population-based cancer registry, with 700 women having follow-up data for >5 years (date of study closure: Dec 31, 2021), yielding an overall 5-year survival estimate (95 % CI) of 56.4 % (52.7 – 60.0 %). KM estimates of 5-year overall survival were obtained to assess differences in cervical cancer survival by SES and HIA. Multivariable Cox-proportional hazards modeling was also conducted, including interaction effects between SES and HIA. Five-year overall survival was lower when comparing low vs. high SES (41.9 % vs 57.9 %, p < 0.0001) and subsidized vs. contributive HIA (45.1 % vs 63.0 %, p < 0.0001). Multivariable Cox modeling showed increased hazard ratios (HR) of death for low vs. high SES (HR = 1.78; 95 % CI = 1.18–2.70) and subsidized vs. contributive HIA (HR = 1.44; 95 % CI = 1.13–1.83). The greatest disparity in HR was among women of low SES affiliated to subsidized HIA (vs. contributive HIA and high SES) (HR=2.53; 95 % CI = 1.62–3.97). Despite Colombia’s universal healthcare system, important disparities in cervical cancer survival by health insurance affiliation and socioeconomic status remain.     

Socioeconomic status,human papillomavirus,and overall survival in head and neck squamous cell carcinomas in Toronto,Canada

BackgroundDespite universal healthcare in some countries, lower socioeconomic status (SES) has been associated with worse cancer survival. The influence of SES on head and neck cancer (HNC) survival is of immense interest, since SES is associated with the risk and prognostic factors associated with this disease.Patients and methodsNewly diagnosed HNC patients from 2003 to 2010 (n = 2124) were identified at Toronto’s Princess Margaret Cancer Centre. Principal component analysis was used to calculate a composite score using neighbourhood-level SES variables obtained from the 2006 Canada Census. Associations of SES with overall survival were evaluated in HNC subsets and by p16 status (surrogate for human papillomavirus).ResultsSES score was higher for oral cavity (n = 423) and p16-positive oropharyngeal cancer (OPC, n = 404) patients compared with other disease sites. Lower SES was associated with worse survival [HR 1.14 (1.06–1.22), p = 0.0002], larger tumor staging (p < 0.001), current smoking (p < 0.0001), heavier alcohol consumption (p < 0.0001), and greater comorbidity (p < 0.0002), but not with treatment regimen (p > 0.20). After adjusting for age, sex, and stage, the lowest SES quintile was associated with the worst survival only for OPC patients [HR 1.66 (1.09–2.53), n = 832], primarily in the p16-negative subset [HR 1.63 (0.96–2.79)]. The predictive ability of the prognostic models improved when smoking/alcohol was added to the model (c-index 0.71 vs. 0.69), but addition of SES did not (c-index 0.69).ConclusionSES was associated with survival, but this effect was lost after accounting for other factors (age, sex, TNM stage, smoking/alcohol). Lower SES was associated with greater smoking, alcohol consumption, comorbidity, and stage.     

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

The survival inequality faced by Indigenous Australians after a cancer diagnosis is well documented; what is less understood is whether this inequality has changed over time and what this means in terms of the impact a cancer diagnosis has on Indigenous people. Survival information for all patients identified as either Indigenous (n = 3168) or non-Indigenous (n = 211,615) and diagnosed in Queensland between 1997 and 2012 were obtained from the Queensland Cancer Registry, with mortality followed up to 31st December, 2013. Flexible parametric survival models were used to quantify changes in the cause-specific survival inequalities and the number of lives that might be saved if these inequalities were removed. Among Indigenous cancer patients, the 5-year cause-specific survival (adjusted by age, sex and broad cancer type) increased from 52.9% in 1997–2006 to 58.6% in 2007–2012, while it improved from 61.0% to 64.9% among non-Indigenous patients. This meant that the adjusted 5-year comparative survival ratio (Indigenous: non-Indigenous) increased from 0.87 [0.83–0.88] to 0.89 [0.87–0.93], with similar improvements in the 1-year comparative survival. Using a simulated cohort corresponding to the number and age-distribution of Indigenous people diagnosed with cancer in Queensland each year (n = 300), based on the 1997–2006 cohort mortality rates, 35 of the 170 deaths due to cancer (21%) expected within five years of diagnosis were due to the Indigenous: non-Indigenous survival inequality. This percentage was similar when applying 2007–2012 cohort mortality rates (19%; 27 out of 140 deaths). Indigenous people diagnosed with cancer still face a poorer survival outlook than their non-Indigenous counterparts, particularly in the first year after diagnosis. The improving survival outcomes among both Indigenous and non-Indigenous cancer patients, and the decreasing absolute impact of the Indigenous survival disadvantage, should provide increased motivation to continue and enhance current strategies to further reduce the impact of the survival inequalities faced by Indigenous people diagnosed with cancer.     

Disparities in cancer stage at diagnosis and survival of Aboriginal and non-Aboriginal South Australians

Background/AimThis study tested the utility of retrospectively staging cancer registry data for comparing stage and stage-specific survivals of Aboriginal and non-Aboriginal people. Differences by area level factors were also explored.MethodsThis test dataset comprised 950 Aboriginal cases and all other cases recorded on the South Australian cancer registry with a 1977–2010 diagnosis. A sub-set of 777 Aboriginal cases diagnosed in 1990–2010 were matched with randomly selected non-Aboriginal cases by year of birth, diagnostic year, sex, and primary site of cancer. Competing risk regression summarised associations of Aboriginal status, stage, and geographic attributes with risk of cancer death.ResultsAboriginal cases were 10 years younger at diagnosis, more likely to present in recent diagnostic years, to be resident of remote areas, and have primary cancer sites of head & neck, lung, liver and cervix. Risk of cancer death was associated in the matched analysis with more advanced stage at diagnosis. More Aboriginal than non-Aboriginal cases had distant metastases at diagnosis (31.3% vs 22.0, p < 0.001). After adjusting for stage, remote-living Aboriginal residents had higher risks of cancer death than Aboriginal residents of metropolitan areas. Non-Aboriginal cases had the lowest risk of cancer death.ConclusionRetrospective staging proved to be feasible using registry data. Results indicated more advanced stages for Aboriginal than matched non-Aboriginal cases. Aboriginal people had higher risks of cancer death, which persisted after adjusting for stage, and applied irrespective of remoteness of residence, with highest risk of death occurring among Aboriginal people from remote areas.