Hanna E. Tervonen

Cancer registration challenges in low- and middle-income countries—the case of the Pacific Islands

1School of Health Sciences, Centre for Population Health Research, University of South Australia, Adelaide, SA, Australia 2Cancer Institute NSW, Alexandria, Sydney, NSW, Australia 3Section of Cancer Surveillance, International Agency for Research on Cancer, Lyon Cedex 08, France 4Centre for Public Health Research, Massey University, Wellington, New Zealand 5South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, SA, Australia

Socio-demographic disadvantage and distant summary stage of cancer at diagnosis--A population-based study in New South Wales.

BACKGROUND Past studies generally indicate that socio-demographic disadvantage is associated with lower cancer survival but evidence of an association with stage of cancer at diagnosis has been less consistent. This study examines the associations between distant summary stage and remoteness, socio-economic status and country of birth in New South Wales for invasive cancers overall and by cancer site. METHODS The population-based New South Wales Central Cancer Registry was used to obtain data on all cases diagnosed in 1980-2009 (n=699,382). Logistic regression models were used to compute odds ratios (ORs) with 95% confidence intervals (CIs) for odds of distant summary stage at diagnosis. RESULTS A higher likelihood of being diagnosed with distant cancer was detected for those living in the most socio-economically disadvantaged areas compared with the least disadvantaged areas (OR 1.27, 95% CI 1.24-1.30) and for those born in other English and non-English speaking countries compared with Australian-born (OR 1.10, 95% CI 1.07-1.12 and OR 1.12, 95% CI 1.10-1.14, respectively) after adjusting for age, sex, diagnostic period, remoteness, socio-economic status and country of birth. Cases living in inner (OR 0.90, 95% CI 0.88-0.91) and outer regional (OR 0.92, 95% CI 0.89-0.94) areas were less likely to be diagnosed with distant stage than cases living in major cities. Odds of distant stage increased over time for those living in socio-economically disadvantaged areas. In cancer site-specific analyses, living in socio-economically disadvantaged areas was generally a stronger predictor of distant stage than remoteness or country of birth. CONCLUSION Our results highlight the importance of lower socio-economic status as a predictor of distant stage at diagnosis. Socio-demographic disadvantage patterns varied for specific cancers, but in general, policy actions are recommended that emphasize earlier detection of cancers in people from lower socio-economic areas.

After accounting for competing causes of death and more advanced stage, do Aboriginal and Torres Strait Islander peoples with cancer still have worse survival? A population-based cohort study in New South Wales

BackgroundAboriginal and Torres Strait Islander peoples in Australia have been found to have poorer cancer survival than non-Aboriginal people. However, use of conventional relative survival analyses is limited due to a lack of life tables. This cohort study examined whether poorer survival persist after accounting for competing risks of death from other causes and disparities in cancer stage at diagnosis, for all cancers collectively and by cancer site.MethodsPeople diagnosed in 2000–2008 were extracted from the population-based New South Wales Cancer Registry. Aboriginal status was multiply imputed for people with missing information (12.9%). Logistic regression models were used to compute odds ratios (ORs) with 95% confidence intervals (CIs) for ‘advanced stage’ at diagnosis (separately for distant and distant/regional stage). Survival was examined using competing risk regression to compute subhazard ratios (SHRs) with 95%CIs.ResultsOf the 301,356 cases, 2517 (0.84%) identified as Aboriginal (0.94% after imputation). After adjusting for age, sex, year of diagnosis, socio-economic status, remoteness, and cancer site Aboriginal peoples were more likely to be diagnosed with distant (OR 1.30, 95%CI 1.17–1.44) or distant/regional stage (OR 1.29, 95%CI 1.18–1.40) for all cancers collectively. This applied to cancers of the female breast, uterus, prostate, kidney, others (those not included in other categories) and cervix (when analyses were restricted to cases with known stages/known Aboriginal status). Aboriginal peoples had a higher hazard of death than non-Aboriginal people after accounting for competing risks from other causes of death, socio-demographic factors, stage and cancer site (SHR 1.40, 95%CI 1.31–1.50 for all cancers collectively). Consistent results applied to colorectal, lung, breast, prostate and other cancers.ConclusionsAboriginal peoples with cancer have an elevated hazard of cancer death compared with non-Aboriginal people, after accounting for more advanced stage and competing causes of death. Further research is needed to determine reasons, including any contribution of co-morbidity, lifestyle factors and differentials in service access to help explain disparities.

Has cancer survival improved for older people as for younger people? New South Wales, 1980–2012

BACKGROUND Cancer survival has improved markedly in Australia for all ages but it is still lower in older patients. We hypothesize that the survival gap by age has increased. Our rationale is that treatment constraints in older people and potentially their limited participation in trials may have limited opportunities for survival gain. METHODS Post-diagnostic five-year cancer-specific mortality rates were analysed by age group for cancers recorded on the NSW Cancer Registry. Live cases were censored on December 31st, 2012. Hazards ratios (HRs) were obtained from proportional hazards regression for 1990-99 and 2000-12 diagnostic periods, using 1980-89 as the reference, adjusting for socio-demographic factors, degree of cancer spread, and for all cancers combined, for cancer sites. RESULTS Five-year mortality reduced by diagnostic period for all cancers collectively from 53% in 1980-89 to 33% in 2000-12, with decreases for separate cancer sites. Adjusted HRs (95% confidence intervals) were 0.78 (0.77, 0.80) for 1990-99 and 0.61 (0.58, 0.63) for 2000-12 for all cancers combined. The downward trend in HRs was smaller for the 80+ year age group, leading to significantly higher HRs of 0.83 (0.81, 0.87) and 0.73 (0.70, 0.76) for 1990-99 and 2000-12 respectively. Results were similar using competing risk regression and 5-year rather than 10-year age strata. CONCLUSION The reduction in cancer mortality was smaller in older people, as seen in the USA. Research is needed to achieve the best trade-offs between cancer control and harm avoidance in older people. Multidisciplinary teams have an important contribution to make.

Does exclusion of cancers registered only from death-certificate information diminish socio-demographic disparities in recorded survival?

BACKGROUND Death Certificate Only (DCO) cancer cases are commonly excluded from survival analyses due to unknown survival time. This study examines whether socio-demographic factors are associated with DCO diagnosis, and the potential effects of excluding DCO cases on socio-demographic cancer survival disparities in NSW, Australia. METHODS NSW Cancer Registry data for cases diagnosed in 2000-2008 were used in this study. Logistic regression was used to estimate the odds of DCO registration by socio-demographic sub-group (socio-economic disadvantage, residential remoteness, country of birth, age at diagnosis). Cox proportional hazard regression was used to estimate the probability of death from cancer by socio-demographic subgroup when DCO cases were included and excluded from analyses. RESULTS DCO cases consisted of 1.5% (n=4336) of all cases (n=299,651). DCO diagnosis was associated with living in socio-economically disadvantaged areas (most disadvantaged compared with least disadvantaged quintile: odds ratio OR 1.25, 95%CI 1.12-1.40), living in inner regional (OR 1.16, 95%CI 1.08-1.25) or remote areas (OR 1.48, 95%CI 1.01-2.19), having an unknown country of birth (OR 1.63, 95%CI 1.47-1.81) and older age. Including or excluding DCO cases had no significant impact on hazard ratios for cancer death by socio-economic disadvantage quintile or remoteness category, and only a minor impact on hazard ratios by age. CONCLUSION Socio-demographic factors were associated with DCO diagnosis in NSW. However, socio-demographic cancer survival disparities remained unchanged or varied only slightly irrespective of including/excluding DCO cases. Further research could examine the upper limits of DCO proportions that significantly alter estimated cancer survival differentials if DCOs are excluded.

The impact of geographic unit of analysis on socioeconomic inequalities in cancer survival and distant summary stage - a population-based study

Objective: When using area‐level disadvantage measures, size of geographic unit can have major effects on recorded socioeconomic cancer disparities. This study examined the extent of changes in recorded socioeconomic inequalities in cancer survival and distant stage when the measure of socioeconomic disadvantage was based on smaller Census Collection Districts (CDs) instead of Statistical Local Areas (SLAs).