Epidemiology%20242:%20Cancer%20Epidemiology

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Epidemiology 242 Cancer Epidemiology

• Zuo-Feng Zhang, MD, PhD
• Fall Quarter, 2009

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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.

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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.

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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

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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.

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Number of deaths for leading causes of death

• 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

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Incidence by sex and cancer site, World 2002
Source Table 1 Parkin DM, et al. CA Cancer J
Clin 2005 55 74-108
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Mortality by sex and cancer site, World
Source Table 1 Parkin DM, et al. CA Cancer J
Clin 2005 55 74-108
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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)

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What is Cancer Epidemiology?
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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.

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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.

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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.

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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.

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Risk factors for Cancer
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Percentage of Cancer Deaths Attributed to Various
Factors (Doll R and Peto R, JNCI, 1981)

• Tobacco Use 30 (25-40)
• Diet35 (10-70)
• Infection 10? (1-?)
• Reproductive Sexual Behavior 7 (1-13)
• Occupation 4 (lt2-8)
• Alcohol 3 (2-4)
• Geophysical factors (natural radiation) 3
  (2-4)
• Pollution 2 (lt1 5)
• Food additive lt1 (-5 2)
• Medicines and Medical Procedures 1 (0.5-3)
• Industrial consumer products lt1 (lt1-2)
• Unknown ?, ?

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Harvard Center for Cancer Prevention
(www.hsph.harvard.edu/cancer)

• Tobacco 30
• Diet in adult life, including obesity 30
• Sedentary lifestyle 5
• Infectious agents 5
• Defects in single genes that run in family 5-10

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Chemical/environmental carcinogens

• 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

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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
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Viral factors

• HPV (human papilloma virus) and Cervix cancer
• EBV(Epstein-Barr virus) and Nasopharyngeal
  cancer, Burkitts lymphoma
• HBV (hepatitis B virus) and hepatocellular
  carcinoma
• HIV (human immunodeficiency virus) and Kaposis
  sarcoma

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