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Measuring Ontario’s Small-Area Inequalities in Cancer (MOSAIC) Study Placemat – Text Version

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Summary

Value

Cancer affects many Ontarians and there are large differences in cancer rates across the province. By identifying health disparities in cancer incidence and survival across Ontario, we can support knowledge users in furthering efforts towards equitable cancer outcomes in their communities. (“Health disparities” and “equitable” as defined in Ontario Health’s Equity, Inclusion, Diversity and Anti-Racism Framework (PDF).)

Knowledge Users

Our anticipated knowledge users include: decision-makers; public health; healthcare providers; communities and patients; advocacy groups and researchers.

Activities

The study will examine cancer incidence and survival amongst adults:

  • Time period: 1999 to 2018
  • Cancer types: breast (female), colorectal, cervical, brain and central nervous system, lung, liver, pancreas, kidney, prostate
  • Geographic areas: municipality and neighbourhood levels (“small-areas”)
  • Underlying factors: socioeconomic status, modifiable risk factors, urban-rural remoteness, screening participation

The study team will engage knowledge users in an Advisory Committee to advise on knowledge product development and dissemination activities.

Impact

  • Short-term: awareness of small-area cancer analysis findings and implications
  • Medium-term: inform programming, advocacy and policy for cancer prevention and treatment
  • Long-term: effect on cancer incidence and survival in Ontario

Background

  • Ontario is Canada’s most populous province (more than 14 million people) with an increasing cancer burden and geographical disparities in cancer incidence and survival[1].
  • Effective cancer control and equitable cancer outcomes require a better understanding of what is influencing inequalities in cancer burden over time (temporal) at the small-area (spatial) level.
  • Recent enhancements to statistical models exist to enable small-area disease mapping and spatial analysis, although these models have yet to be applied in Canada.
  • Study aim: to produce valid and robust small-area estimates of cancer incidence and survival among Ontario adults to identify and investigate inequalities.

Objectives

  1. Identify spatio-temporal inequalities in cancer incidence and relative survival among the cancers of interest
  2. Explore underlying factors that may be driving spatio-temporal inequalities in cancer incidence and survival
  3. Engage knowledge users in the research process to enhance utility and reach of study findings

Objective 1: Identify

Population

  • Ontario adults (ages 20 to 89) diagnosed with primary cancers between 1999 and 2018 (“primary cancer” refers to the first diagnosis of a specific cancer, as it is possible to have more than one primary cancer).
  • Cancer types: Ontario screening programs (breast, colorectal, cervical), difficult to treat (brain and central nervous system, lung, liver, pancreas), emerging types (kidney, prostate)

Geography

  • Census dissemination areas: 400 to 700 people (neighbourhoods)[2]
  • “Uber” Census Tracts: newly created hybrid of Census Subdivisions (municipalities)[3] in rural areas (up to 110,000 people) and Census Tracts in urbanized areas (2,500 to 8,000 people)[4]

Analysis

Incidence

  • Cross-sectional design
  • Indirectly standardized incidence rate ratios at the dissemination area level
  • Hierarchical Bayesian spatio-temporal modeling[5]

Survival

  • Retrospective cohort design
  • Excess mortality odds ratios at the Uber Census Tracts or Census Subdivisions level
  • Hierarchical Bayesian spatio-temporal flexible parametic relative survival modeling[6]

Objective 2: Explore

  • Underlying factors :
    • Up to 6 modifiable cancer risk factors[7]
    • Participation in 3 cancer screening programs[8]
    • Select dimensions of marginalization (socioeconomic status)[9]
    • Six categories of urban-rural remoteness, from large urban (500,000 or greater) to rural-very remote (less than 10,000)
  • All underlying factors explored for incidence. Select factors (socioeconomic status and urban-rural remoteness) will be examined for survival.

Objective 3: Engage

  • Involve knowledge users in assessing study outputs (data visualizations), advising on knowledge products and informing dissemination planning.
  • Invite stakeholders from knowledge user groups to participate in an Advisory Committee.
  • Key activity: a user engagement workshop with the Committee to facilitate feedback and discussion.

Contact

What kind of knowledge products would help you use this information to inform your practice or policy decisions? Email mosaicstudy@ontariohealth.ca.

References

  1. Cancer Care Ontario. Ontario Cancer Statistics 2018. https://www.cancercareontario.ca/en/statistical-reports/ontario-cancer-statistics-2020. Published 2018. Accessed March 1, 2021.
  2. Statistics Canada. Illustrated Glossary: Dissemination area (DA) definition. https://www150.statcan.gc.ca/n1/pub/92-195-x/2016001/geo/da-ad/da-ad-eng.htm. Accessed January 17, 2022
  3. Statistics Canada. Illustrated Glossary: Census subdivision (CSD) definition. https://www150.statcan.gc.ca/n1/pub/92-195-x/2016001/geo/csd-sdr/csd-sdr-eng.htm. Accessed January 17, 2022
  4. Statistics Canada. Illustrated Glossary: Census Tract (CT) definition. https://www150.statcan.gc.ca/n1/pub/92-195-x/2016001/geo/ct-sr/ct-sr-eng.htm. Accessed January 17, 2022
  5. Lee D, Rushworth A, Napier G. CARBayesST: An R Package for Spatio-temporal Areal Unit Modelling with Conditional Autoregressive Priors. R Package Version 2. 2015.
  6. Cramb SM, Mengersen KL, Lambert PC, Ryan LM, Baade PD. A flexible parametric approach to examining spatial variation in relative survival. Stat Med. 2016;35(29):5448-5463. doi:10.1002/sim.7071
  7. Cancer Care Ontario. Cancer Risk Factors Atlas of Ontario. https://www.cancercareontario.ca/en/statistical-reports/cancer-risk-factors-atlas-ontario. Published 2017. Accessed March 15, 2021.
  8. Cancer Care Ontario. Screening Programs – Cancer Care Ontario. https://www.cancercareontario.ca/en/cancer-care-ontario/programs/screening-programs. Accessed March 15, 2021.
  9. Ontario Community Health Profiles Partnership. Ontario Marginalization Index (ON-Marg). http://www.ontariohealthprofiles.ca/onmargON.php. Accessed March 15, 2021

This study was conducted with the support of the Ontario Institute for Cancer Research through funding provided by the Government of Ontario.