Presentation of study findings at the annual meeting of the American Public Health Association, Philadelphia, 2009 (Gorey et al., The Breast Journal, 2010)

1. Long-Term Breast Cancer SurvivalLong-Term Breast Cancer Survival
Comparisons of Low-Income Urban
Neighborhoods in Ontario and
California, 1988 to 2006

2. Co-InvestigatorsCo-Investigators
Investigator Expertise ______
Kevin Gorey Social epidemiology
Karen Fung Biostatistics
Isaac Luginaah Medical geography
Caroline Hamm Medical oncology
Eric Holowaty Cancer registration/surveillance

3. Presenter DisclosuresPresenter Disclosures
No relationships to disclose
Funding sources:
Canadian Institutes of Health Research
Assumption University (Research Chair)
Manuscript status
The Breast Journal (in press)

4. Why study breast cancer? It’s aWhy study breast cancer? It’s a
sentinelsentinel health care quality indicator.health care quality indicator.
Relatively common over the life course
Effective screens and treatments exist
Timely diagnosis and treatment matter
Excellent prognoses can be expected
Node Negative Breast Cancer
Treatment advances proliferated
Substantial 15-yr outcome variability

5. Political ContextPolitical Context
Canada
Anecdotes about health care failures
• Long waits & scare resources
Prevalent advocacy for private solutions
United States
Prevalent under- & uninsured populations
Public options being considered

6. Scientific Context: Ontario-California BreastScientific Context: Ontario-California Breast
Cancer Care & Survival in Low-IncomeCancer Care & Survival in Low-Income
AreasAreas
Significant Ontario advantages, 1998-2006
• Shorter wait-times & greater access to
radiation therapy
• Better 5-yr survival (node +ve disease)
15-yr node +ve survival null, 1988-2006
No previous Canada-US study of long term
node –ve breast cancer survival

7. Research Question: HypothesesResearch Question: Hypotheses
Have breast cancer care advances that proliferated
during the past generation been enjoyed
equitably by low-income Canadian and
American women with the most treatable type
of breast cancer?
Hypotheses:
1. Significantly more such women in Ontario
survived 15 years after their diagnosis.
2. They enjoyed significantly better treatment
access than their counterparts in California.

8. MethodsMethods
Comparison of Historical Cohorts:
Urban Places in Ontario and California,
Women Diagnosed Between 1988-1990
Followed Until 2006 (15 Years)

9. SamplesSamples
Enhanced Ontario and California Cancer Registries
• Comprehensive (98%), reliable, validity
• 95+% valid data for all study variables
Random samples stratified by large-small places
• Toronto-San Francisco & Windsor-Modesto
Restricted to node –ve disease diagnosed 1988-90:
• Analytic sample of 800 women
Comparable places defined by Census Bureaus
• Census tract (CT) low-income prevalence

10. AnalysesAnalyses
Cohorts followed for all-cause 15-year
survival (yes/no) until 2006
Age-adjusted, income-survival rate
ratios observed within- and
between-country income deciles
Confidence intervals based on the
Mantel-Haenszel χ2
test

11. ResultsResults

12. Within-CountryWithin-Country
15-Yr Survival Rate Ratios (95% CIs)15-Yr Survival Rate Ratios (95% CIs)
IncomeIncome OntarioOntario CaliforniaCalifornia
High 1.00 … 1.00 …
0.88 (0.54,1.42) 1.00 (0.96,1.04)
1.01 (0.88,1.16) 0.85 (0.56,1.30)
1.10 (0.78,1.55) 1.01 (0.65,1.56)
0.91 (0.54,1.52) 0.91 (0.65,1.28)
1.05 (0.78,1.42) 0.56 (0.34,0.92)
0.94 (0.55,1.62) 0.69 (0.48,0.99)
1.02 (0.65,1.61) 0.84 (0.53,1.33)
1.09 (0.77,1.54) 0.84 (0.54,1.31)
Low 0.96 (0.60,1.54) 0.60 (0.37,0.97)

13. Between-Country Findings:Between-Country Findings:
All Indicative of Ontario AdvantageAll Indicative of Ontario Advantage
Lowest income decile (N = 80):
• 15-yr survival RR 1.66 (1.00, 2.76)
Vulnerable places (lowest 6th
, 7th
& 10Th
income deciles, N = 240):
• 15-yr survival RR 1.35 (1.01, 1.81)
• Lumpectomy RR 1.86 (1.37, 2.52)
• Adjuvant RT RR 1.75 (1.21, 2.53)

14. DiscussionDiscussion

15. SummarySummary
Low-income women with node –ve breast
cancer in Ontario were advantaged on
care and 15-year survival as compared to
women in California.
In an era of treatment innovations, relatively
poor women in Ontario gained access to
them much more readily than did their
counterparts in California.
Such access mattered in terms of their
long-term survival chances.

16. LimitationsLimitations
1. Race/Ethnicity Alternative Explanation
Findings replicated among non-
Hispanic white women in California vs.
entire diverse Ontario sample
2. All-Cause vs. Cancer-Specific Survival
Findings replicated among women
younger than 50 at diagnosis

17. ConclusionConclusion
More inclusive health insurance
coverage in Canada versus the
United States seems the most
plausible explanation for the large
observed Canadian advantages on
treatment access and survival.