Transcript Introduction to Cancer Epidemiology

Introduction to Cancer
Epidemiology
Faina Linkov, PhD
Research Assistant Professor of Medicine and Epidemiology
University of Pittsburgh Cancer Institute
E-mail (preferred mode of communications): fyL1 (at)
pitt.edu
University of Pittsburgh Graduate School
of Public Health, one of the oldest school to
advocate for chronic disease epidemiology
research
What this course is about
• Learning more about cancer epidemiology
• Investigating risk factors implicated in
cancer development
• Learning to write grants and critique articles
• Learning to be passionate about chronic
disease epidemiology
True or False?
Smoking causes lung cancer
True or False?
Large percentage of cancers are
preventable
True or False?
In the past 20 years tremendous
improvements in the treatment
of all cancers have been
achieved
True or False?
Preventing cancer is easier than
treating cancer
True or False?
Screening tests are available for
most cancers
Epidemiology
“Distribution and
determinants of
disease frequency
in human
populations”
Cancer Epidemiology
Historical Perspective
1775
British surgeon, Percival
Pott reported probably
the first description of
occupational
carcinogenesis in the
form of scrotum cancer
among chimney sweeps.
Cancer Epidemiology
Historical Perspective
Tight corsets and cancer
1842
Rigoni-Stern, Italian physician, observed
that married women in the city were
getting cervical cancer, but nuns in
nearby convents weren’t. He also
observed that nuns had higher rates of
breast cancer, and suggested that the
nuns’ corsets were too tight.
Five Criteria for a Cause  Effect Relationship
Criteria
Risk Factor for Disease
1) Timing
 Exposure occurs before
2) Strength
3) Prevalence
4) Relationship to
other risk factors
5) Plausibility
development
of disease or during its progression
 Is dose-dependent
 Cessation of exposure can modify disease
 Occurs in multiple populations
 Is independent
 Can also act synergistically
 Produces structural‡ or functional changes
which are events in mechanism of disease
‡ anatomic or molecular
Cancer Epidemiology
Historical Perspective
1700s: tobacco and cancer
Reports of cancer risks associated with
tobacco in the 18th century included
snuff taking and nasal cancer, reported
by Hill in 1761, and pipe smoking and lip
cancer by von Soemmering in 1795.
Cancer Epidemiology
Historical Perspective
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Tobacco and Lung Cancer
Asbestos and Lung Cancer
Leather Industry and Nasal Cancer
Dyes and Bladder Cancer
Ionizing Radiation and Many Cancers
DES and Vaginal Adenocarcinoma
EBV and Burkitt’s Lymphoma
HPV and Cervical Cancer
Cancer Epidemiology
An Introduction
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The Epidemiologic Perspective
Aims of Cancer Epidemiology
Methods of Epidemiology
Historical Perspective and Examples
Contemporary Studies
The Future
Aims of Cancer Epidemiology
• Uncover new etiologic leads
– study of the distribution of cancer
– quantify the risk associated with different
exposures and host factors
• Promote insights into the mechanisms of
carcinogenesis
• Assess efficacy of preventive measures
• Investigate predictors of survival
Types of Epidemiologic Studies
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Cohort
Case-Control
Cross-Sectional (Prevalence)
Other
Methods of Cancer Epidemiology
• Descriptive Studies
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Incidence, mortality, survival
Time Trends
Geographic Patterns
Patterns by Age, Gender, SES, Ethnicity
• Analytic Studies
– Case-control
– Cohort
Challenges to Interpretation
– Observational vs. Experimental Design
– Cancer “clusters”
– Study Design and Conduct
• Study Size
• Biases: Misclassification, confounding, selection
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Exposure assessment important
Epidemiology and “strong” and “weak” effects
Impact on a population level
Replication critical
Cancer Epidemiology
Sources
• US SEER Registry System
• IARC International Registries
• State/Hospital Registries
• Etiologic Clues
– “Alert” Clinician
– Experimental Studies
Cancer Epidemiology
Current/Future Topics
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Infectious Agents
Cancer and inflammation
Obesity
Physical Activity
Diet
Hormones
Immunologic Factors
Cancer disparities
Inherited Susceptibility (Polymorphisms)
Cancer Epidemiology
Current/Future Topics
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Tumor (somatic) Alterations
Cancer Classification
Biomarkers of Exposure/Effect
Vaccines
Survivorship
Cancer and disability
Alternative therapy