Healthcare Access, SES, and Late-Stage
Cancer Diagnosis: Public Policy
Implications
Sara McLafferty
Department of Geography and GIS
University of Illinois at UrbanaChampaign
“On Airs, Waters and Places …”
Hippocrates c. 400 B.C.
Place, space, and health
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Places – environments infused with meaning
Complex pathways link place characteristics and
health
Spatial characteristics of places are important
People experience places differently
“People create places and places create people”
(MacIntyre and Ellaway 2003)
Crosscutting trends
Public Health
“New” public health –
context, environments
• Risky environments
(Rhodes et al. 2005)
• Social epidemiology
(Diez Roux 2010)
• Built environment
(Hembree et al. 2005)
Spatial Analysis
Data and methods for
geographical analysis
• Huge increase in spatial
and environmental data
• Geographic information
systems (GIS)
• Spatial analysis
methods and software
How can we leverage these trends to enhance cancer control
and prevention through effective place-based interventions?
Organization of presentation
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Overview of place, space and spatial
analysis
Geographic disparities in cancer
Geographic foundations for cancer control,
prevention and intervention
• Spatial targeting
• Spatial tailoring
• Spatial generating
Spatial analysis methods: tools for
visualizing, analyzing and modeling
geospatial information about places
Spatial Data
• Information linked to a place (s, y, t)
– Place/location (s)
– Attribute (y)
– Time (t)
• Spatial data have characteristic geometries
Spatial perspective:
Distance
Pattern
Proximity
Place
Detailed characteristics of people and
environment in a locality, and
meanings and experiences associated
with environment
Spatial analysis methods are used to visualize, explore
and model spatial data and their interrelationships
How Chicago would look if %
black population had a random
spatial distribution
The actual spatial distribution of %
black population shows strong
spatial autocorrelation
% Black Population
< 20
20 - 40
40 - 60
60 - 80
80 - 100
Spatial perspectives help us to “see” places more effectively
Low birthweight infants, Brooklyn NY, 2000
Hotspot mapping
Kernel Density Estimation
s =  k di
di<
Where:
s = est. density at grid point s
di = distance from point i to grid point s
 = bandwidth
k( ) = kernel function
Move a filter across the map
LBW Density, 1.0 mile bandwidth
LBW Density, 2.0 mile bandwidth
How do these concepts relate to cancer
research, control, and Intervention?
Cancer Disparities:
“Distinguished by race/ethnicity, gender, age, socioeconomic status,
geographic location, occupation, and education, underserved
population groups across the United States suffer disproportionately
high cancer incidence and mortality rates for a variety of reasons.
These individuals are significantly more likely than the overall U.S.
population to:
Be diagnosed with and die from preventable cancers.
Be diagnosed with late stage disease for cancers detectable at an
early stage through screening …”
“Overcoming Cancer Disparities,” http://plan2006.cancer.gov/disparities.shtml
Cancer incidence
Screening
Early diagnosis
Vary from
place to place
Treatment
Care
reflecting complex individual, socioeconomic, health care,
and environmental factors
Geographic inequalities in cancer incidence:
Predicted U.S. cervical cancer incidence (A) and mortality rates (B) by county, 1995 to 2004.
Horner M et al. Cancer Epidemiol Biomarkers Prev
2011;20:591-599
©2011 by American Association for Cancer Research
Geographic inequalities in cancer incidence:
Age-adjusted incidence rate of all childhood (ages 0-19) cancers in males
by Health Service Area, 1995-2006
Zhu, L., Pickle, LW, Zou, Z, Cucinelli, J. (2014) Trends and patterns of childhood cancer
incidence in the United States, 1995-2010. Statistics and its Interface, 7, 121-134.
Spatial filtering reveals
geographic variation in
colorectal cancer
incidence in Iowa
Beyer, K., Tiwari, C., Rushton G. (2012) Five
essential properties of disease maps,
Annals of the AAG, 102, 1067-75.
Cancer screening varies from place to place
Percent of women ages 18 years and more who reported having had a Papanicolaou smear
test within the past 3 years by county—continental United States, 2000 to 2003.
Horner M et al. Cancer Epidemiol Biomarkers Prev
2011;20:591-599
©2011 by American Association for Cancer Research
Strong geographic disparities exist in cancer
stage at diagnosis
Late-Stage Breast
Cancer Diagnosis varies
across Illinois
Mammography facilities are
not available in many places
of high late-stage risk
Rural-Urban Gradient in Late-stage Cancer
McLafferty S., Wang F. (2009). Rural Reversal? Risk of late-stage
cancer across the rural-urban continuum in Illinois. Cancer,
Access to health care resources for
cancer screening and treatment is
geographically and socially uneven
Uneven
Access to
Oncologists
And Primary Care
Physicians
And access to cancer treatment resources differs socially and spatially: Vulnerable
populations often have limited access to, and are less likely to utilize, the most
effective cancer treatments
Onega T. et. al. (2010) Influence of place of residence in access to
specialized cancer care for African-Americans. Journal of Rural
Health, 26, 12-19.
Our research in Illinois shows that places
are associated with late-stage cancer via:
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Socioeconomic disparities
• Low incomes
• Vulnerable, high-need populations
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Access to primary care services
• Only outside Chicago
• Transportation barriers
How can we leverage our ability to
map, analyze, and understand the
relationships between place, space,
and cancer to inform treatment and
control policies and interventions?
Geospatial contributions
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Spatial (place) targeting
Spatial (place) tailoring
Spatially generating
Spatial Targeting
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Focus resources and interventions to highprevalence, high-risk places
Methods
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Hotspot mapping
Heat mapping
Spatial cluster detection
Risk mapping
Hotspot
Spatial Targeting
• Rooted in infectious disease control and eradication
activities
• Smallpox eradication (Henderson 1980)
– Disease surveillance
– “highly targeted, intensive containment vaccination (p.
426)”
Rationale for spatial targeting:
Geographically bounded processes
Carter R., Mendis K, Roberts R. (2000) Spatial targeting of interventions against
Malaria. Bull World Health Assoc, 78, 1401-1411
Spatial targeting for other types of health
issues
Rationale is
primarily economic
Petersen J. et al. (2009) Teenage pregnancy: New tools to support
local health campaigns. Health & Place, 15, 300-307
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Need to think more critically about spatial
targeting
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Where to target? Where are the hotspots?
Hotspots are heterogeneous
Hotspots in cold spots
Hidden populations
Stigmatization
Where is the
Hotspot?
Clusters of high LBW among
infants born to immigrant
mothers in Brooklyn & Queens,
2000
SaTScan
Hotspots are Heterogeneous
Clusters of High LBW Among Immigrant Infants
CLUSTER
1
2
0
2
4
8 Miles
Caribbean
Hotspots differ in
Immigrant population composition, housing
characteristics, population density, access to
public transportation
South America
South Asia
Mexico
SubSaharan
Africa
Caribbean
South America
South Asia
Mexico
SubSaharan
Africa
0
2
4
8 Miles
Hot spots within cold spots
In small metropolitan areas in Illinois, the risk of late
breast cancer diagnosis is low for most women, but
very high for African-American women
% Late-stage
breast cancer
diagnosis
Other
32.1%
African-American
45.6%
Hotspots reflect the interlocking effects
of people and places
Spatial tailoring
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Place-specific customizing of interventions
Detailed knowledge of local environment,
people’s livelihoods and economic well-being,
sociocultural characteristics, spatial
interactions, processes that put people at risk
Place characteristics (people & environment)
affect design and implementation
• Smallpox eradication, Afghanistan
• Not-on-Tobacco, West Virginia (Rothermel et al.
2011)
Kreuter MW, Skinner CS (2000) Tailoring: What’s in a
name? Health Educ Res, 15(1), 1-4
Community mapping to support Healthy Start
(Aronson et al. 2007)
Examples of place characteristics important for maternal &
infant health:
Houses of worship
Businesses
Liquor licenses
Vacant houses
Aronson RE, Wallis AB, O’Campo PJ, Schafer P (2007).
Neighborhood mapping and evaluation: A methodology
for participatory community health initiatives. Matern
Child Health J, 11, 373-83.
Spatially Generating
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Community input in design of
interventions
• Bottom-up participatory processes
• Local knowledge
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Participatory GIS (PGIS)
Colorectal cancer intervention in Storm Lake, IA
Beyer KMM, Comstock S, Seagren R. (2010) Disease maps as context for community mapping. J Community Health,
33, 635-44.
Summary
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Place matters!
Cancer inequalities patterned over space
Diverse populations have diverse geographies
and diverse experiences of place
Geography affects social interactions,
environmental exposures and access to resources
and services
We can leverage these understandings to
improve cancer control and prevention through
the thoughtful application of strategies of
spatial/place targeting, tailoring and generating
THANK YOU!