Transcript Epidemiology 242: Cancer Epidemiology

Epidemiology 242: Cancer
Epidemiology
Zuo-Feng Zhang, MD, PhD
Fall Quarter, 2009
Overall Objectives of the Course
• The overall objectives are to introduce basic
concept in cancer epidemiology, including
concepts of carcinogenesis, multistage
models, pre-malignant lesion, international
patterns of cancer.
Overall Objectives of the Course
• To discuss major etiologic issues for a variety of
cancers including smoking, alcohol drinking, virus,
radiation, nutrition, occupational and environmental
exposures.
• To review epidemiological data on major cancers
including prostate, breast, lung, and other cancers.
• To lecture on the basic concepts of molecular and
genetic epidemiology.
Introduction to Cancer Epidemiology
• (1) To overview the cancer magnitude
• (2) To familiarize students with basic concepts
of tumor and its classification
• (3) To introduce basic concept of
carcinogenesis and cancer epidemiology
Why Cancer is a Major Public Health
Problem?
• Improved medical care and public health have lead
to:
• Decrease and control of common diseases of
childhood and infectious disease, the major causes
of death in the past
• the increase of life expectation
• the increase of the proportion of aging population,
since cancer is generally considered as an aging
disease, cancer becomes a major public health
problem.
Number of deaths for leading causes
of death
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Heart disease: 631,636
Cancer: 559,888
Stroke (cerebrovascular diseases): 137,119
Chronic lower respiratory diseases: 124,583
Accidents (unintentional injuries): 121,599
Diabetes: 72,449
Alzheimer's disease: 72,432
Influenza and Pneumonia: 56,326
Nephritis, nephrotic syndrome, and nephrosis: 45,344
Septicemia: 34,234
Incidence by sex and cancer site, World 2002
Source: Table 1: Parkin DM, et al. CA Cancer J Clin [2005]; 55: 74-108
Mortality by sex and cancer site, World
Source: Table 1: Parkin DM, et al. CA Cancer J Clin [2005]; 55: 74-108
The Major Cancers
• Lung (ICD-10 C33 and C34)
• Breast (female, C50)
• Colon/rectum (C18-C20)
• Stomach (C16)
• Prostate (C61)
• Liver (C22)
• Cervix uteri (C53)
• Esophagus (C15)
What is Cancer Epidemiology?
Definition
• Cancer epidemiology is the study of the pattern of
cancer in populations.
• Its essential aim is to identify causes of cancer,
including preventable (avoidable) causes and
inherited tumor susceptibility.
• It is also play an critical role in many other areas of
cancer research including evaluation of screening
effects, cancer prevention and control
• Current studies directions includes molecular and
genetic epidemiology of cancer.
Types of Epidemiologic Studies
• Descriptive Epidemiologic study: To describe
the difference in occurrence of a particular
cancer between different groups (age, gender,
race, country, a period of time for time trend)
and to generate the hypothesis for
increased/decreased for the specific tumor
type.
Types of Epidemiological Studies
• Analytic Epidemiology: To study risk factors or
potential causes of cancer by a particular
study design, e.g., case-control study or
cohort study.
Types of Epidemiological Studies
• Intervention studies: Applying the knowledge
(risk/protective factors) obtained from
analytic epidemiological studies to specific
population in order to reduce the risk of
cancer.
Risk factors for Cancer
Percentage of Cancer Deaths Attributed to Various Factors
(Doll R and Peto R, JNCI, 1981)
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Tobacco Use: 30% (25%-40%)
Diet:35% (10%-70%)
Infection: 10%? (1%-?)
Reproductive & Sexual Behavior: 7% (1%-13%)
Occupation: 4% (<2%-8%)
Alcohol: 3% (2%-4%)
Geophysical factors (natural radiation): 3% (2-4%)
Pollution: 2% (<1% – 5%)
Food additive: <1% (-5% – 2%)
Medicines and Medical Procedures: 1% (0.5%-3%)
Industrial consumer products <1% (<1%-2%)
Unknown: ?, ?
Harvard Center for Cancer Prevention
(www.hsph.harvard.edu/cancer)
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Tobacco: 30%
Diet in adult life, including obesity: 30%
Sedentary lifestyle: 5%
Infectious agents: 5%
Defects in single genes that run in family: 510%
Lichtenstein P, Holm NV, Verkasalo PK, Iliadou A, Kaprio J, Koskenvuo M, Pukkala E, Skytthe A,
Chemical/environmental carcinogens
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Smoking and lung cancer
Sun exposure and squamous cell carcinoma of skin
Asbestos exposure and lung cancer
Smoke food risk with nitrosamines and
adenocarcinoma of the stomach
• Alcohol drinking and squamous cell carcinoma of
esophagus
• Aflatoxin B1 and liver cancer
Radiation
• Exposure to ultraviolet radiation (in the form
of sunlight) and squamous cell carcinoma of
skin
• Ionizing radiation is related to skin cancer and
leukemia in radiologist
Viral factors
• HPV (human papilloma virus) and Cervix cancer
• EBV(Epstein-Barr virus) and Nasopharyngeal cancer,
Burkitt’s lymphoma
• HBV (hepatitis B virus) and hepatocellular carcinoma
• HIV (human immunodeficiency virus) and Kaposi’s
sarcoma
http://www.yourdiseaserisk.wustl.edu/hccpquiz.pl?lang=english&func=home&page=cancer_index