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Unequal impact: Maori and non-Maori cancer statistics International Group for Indigenous Health Measurement, 28-30 November, 2006 Canberra Donna Cormack Te Ropu Rangahau Hauora a Eru Pomare Acknowledgements Te Ropu Rangahau Hauora a Eru Pomare (Bridget Robson) Gordon Purdie (Biostatistician), Department of Public Health Contracted by the Ministry of Health Acknowledge the individuals and organisations who contributed Overview Background Context of the Cancer Chartbook: ‘Unequal Impact’ Issues Results Summary Context “Maori are tangata whenua. Not people in the land or over the land, but people of it” (Moana Jackson, 1993) We have rights to good health (health care and healthy environments) We have a right to determine our own health priorities and futures We have rights to monitor the impact of Crown policy, action and inaction We have rights to be counted as a population in our own right Meeting these rights requires comprehensive, detailed, accurate information Cancer control context Recent developments in cancer control policy Cancer Control Strategy launched in 2003 Establishment of a Cancer Control Council New Zealand Cancer Control Strategy Action Plan: 2005-2010 Evidence of increasing ethnic gaps in cancer mortality over the 1980s and 1990s Little detailed information available on cancer for Maori Measurement issues Issues with the quality and completeness of data The implications of different standards ‘Ever Maori’ Standardising to the Maori population Assumptions and generalisations driving research questions and framing of results ‘late presentation’ ‘aggressive tumours’ ‘non-compliance’ Data issues Data Sources: Cancer Register and mortality data 1995-2001, and hospital admissions 1996-2003, NZHIS We know that Maori are undercounted in cancer registrations, hospital admissions and deaths ‘Ever Maori’: count as Maori anyone ever recorded as Maori in any of the data sources or on the NHI during the analysis period Ethnicity data: Estimate Maori cancer registrations undercounted by 17%, deaths by 6%, Classification of ethnicity: “Ever Maori’ method reduced undercount to <1%, numbers of unassigned ethnicity decreased Has been used in other analyses Chartbook analyses Stage at diagnosis: from extent of disease data on cancer registration: % localised, regional, distant, unknown. Maori:non-Maori odds ratios for stage, adjusted for age, using logistic regression Survival data: cancer-specific mortality, censored at death if died from other causes or at 31 December 2001 Survival curves – Kaplan-Meier estimates (unadjusted) Hazard ratios – Maori/non-Maori relative risk of death after diagnosis; proportional hazards model, adjusted for age and sex, and for stage; also calculated by stage. Choice of standard population Differences in age structures: Maori (relatively young) and non-Maori (relatively old) Segi’s world population and WHO world population both used in Aotearoa Maori population considerably younger and non-Maori considerably older Magnitude of age-standardised incidence and mortality rates generally increased (Maori, Segi, WHO) while ratio ratios remained fairly similar Rates standardised to Maori population reflect Maori realities more closely than those adjusted to older standards Maori Non-Maori Rate ratios Maori Segi WHO Maori Segi WHO Maori Segi WHO 220.9 378.4 425.0 187.8 319.2 359.1 1.18 1.19 1.18 Results: leading cancer sites Leading cancer registration sites differ for Mäori and non- Mäori, in terms of ranking and percentage of new cases or deaths Most commonly occurring cancers: - lung, stomach, cervix, testis and liver more common - colorectal, melanoma, prostate, bladder and brain less common Leading causes of cancer death: - cervix and liver more common for Mäori - melanoma more common for non-Mäori Leading cancer registration sites 1996-2001 Maori Non-Maori Number % of new cases Number % of new cases Trachea, bronchus & lung 1,437 19.4 Prostate 15,324 16.3 Female breast 1,147 15.9 Colorectal 14,410 15.3 Prostate 632 8.5 Female breast 11,762 12.5 Colorectal 514 6.9 Melanoma of skin 9,372 9.9 Stomach 329 4.4 Trachea, bronchus & lung 7,975 8.5 Leukaemias 276 3.7 Bladder 3,284 3.5 Cervix uteri 250 3.4 Non-Hodgkin’s lymphoma 3,256 3.5 Non-Hodgkin’s lymphoma 232 3.1 Leukaemias 3,133 3.3 Liver & intrahepatic bile ducts 183 2.5 Stomach 2,019 2.1 Pancreas 176 2.4 Kidney 1,835 1.9 Site Site Both sexes Leading cancer death sites 1996-2001 Maori Non-Maori Number % of cancer deaths Number % of cancer deaths 1,370 32.0 Trachea, bronchus & lung 7,107 17.3 Female breast 383 8.9 Colorectal 6,502 15.8 Colorectal 292 6.8 Female breast 3,435 8.3 Stomach 277 6.5 Prostate 3,111 7.6 Prostate 178 4.2 Non-Hodgkin’s lymphoma 1,656 4.0 Pancreas 168 3.9 Pancreas 1,651 4.0 Liver & intrahepatic bile ducts 153 3.6 Stomach 1,537 3.7 Leukaemias 137 3.2 Leukaemias 1,392 3.4 Non-Hodgkin’s lymphoma 111 2.6 Melanoma of skin 1,352 3.3 95 2.2 Brain 1,174 2.9 Site Site Both sexes Trachea, bronchus & lung Brain Mapping cancer disparities Age-standardised incidence rate for all sites: - 220.9 per 100 000 for Mäori -187.8 per 100 000 for non-Mäori - relative risk of 1.18 (95% CI 1.15-1.21) Age-standardised mortality rate for all sites: - 127.9 per 100 000 for Mäori - 66.3 per 100 000 for non-Mäori - relative risk of 1.93 (95% CI 1.87-1.99) Cancer-specific survival is lower for most types of cancer Maori/non-Maori age-standardised cancer incidence & mortality ratios 1996-2001 All sites Lung Breast Prostate Colon Rectum Stomach Cervix Uterus Testis Mäori/non-Mäori Age-standardised Rate Ratio (log scale) 10.0 4.85 4.25 3.70 3.31 3.69 3.08 2.27 2.28 1.93 1.68 1.18 1.84 1.61 1.61 1.21 1.17 1.0 0.84 0.76 0.58 Deaths Registrations 0.1 0.76 Hazard ratios Relative risk of death (age-sex adjusted) after diagnosis significantly higher for Mäori for: Lung 1.34 Uterus 1.65 Breast 1.69 Kidney 1.52 Prostate 2.33 Oral cancers 2.07 Colorectal 1.67 Liver 1.39 Cervix 2.68 Oesophagus 1.74 Stomach 1.57 Bladder 2.37 Stage at diagnosis (extent of disease spread) Maori are less likely to have stage recorded for cancers of the: lung breast cervix colorectal stomach uterus oesophagus brain 1.41 1.29 1.86 2.19 1.63 2.13 1.79 1.90 OR adjusted for age at diagnosis Distribution of stage at diagnosis Colorectal cancer 1996-2001 % 50 40 30 20 10 0 Localised Regional Mäori Distant non-Mäori Unknown Stage at diagnosis (staged cancers only) • Adjusted for age & sex, Maori are significantly less likely to be diagnosed at localised stage for: breast trachea, bronchus & lung colorectal cervix prostate testis kidney lip, oral cavity & pharynx melanoma Stage at diagnosis (staged cancers only) • Adjusted for age & sex, Maori are significantly more likely to be diagnosed at distant stage for: colorectal trachea, bronchus & lung breast cervix prostate melanoma Impact on survival disparities HR Age adjusted Lung 1.34 HR Age & stage adjusted 1.28 Breast 1.69 1.48 31% Cervix 2.68 2.34 20% Colorectal 1.67 1.34 50% Prostate 2.33 1.70 47% Kidney 1.52 1.36 31% % reduced 17% Maori/non-Maori hazard ratios by stage (adjusted for age) Localised Regional Distant Stomach Unknown 1.98 1.70 1.77 1.68 Colorectal 2.00 1.56 1.11ns 1.54 Lung 1.76 1.55 1.20 1.29 Breast 1.87 1.34 1.34ns 1.76 Cervix 2.38ns 2.42 3.87 1.93 Prostate 0.97ns 1.23ns 1.55 1.92 ns=not significant at 5% level Stage at diagnosis Differential stage at diagnosis accounts for part but not all of the disparity in cancer-specific survival between Mäori and non- Mäori At each stage, Mäori cancer-specific mortality after diagnosis is higher than non- Mäori for many cancers This indicates the likely existence of disparities in timely access to definitive diagnostic procedures, staging procedures, and optimal treatment/management of cancer Assumptions and generalisations Challenges assumptions about explanations for disparities in cancer experiences and outcomes late presentation or late diagnosis non-compliance or unequal treatment Requires us to look more closely at the role of health systems and health care processes Summary Need to be able to measure and monitor cancer disparities ‘Ever Maori’ can mitigate undercount Requires good quality, consistent, standardised data Kaupapa Maori approach can meet everyone’s needs Need to be able to establish priorities for Maori cancer control Requires depth, breadth and detail of information Need to think critically about the way we talk about Maori cancer and cancer inequalities Requires us to challenge assumptions underpinning research questions and the framing and interpretation of results