Lung cancer: a preventable disease

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Lung cancer a preventable disease

• Epidemiology addresses issues related to ?
• Heredity,
• Life-style, and
• Environment.

Censina R. Apap, MD FCCP
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Lung cancer how did it start?

• First described in 1420 in Schneeberg-Austria
  after the opening of cobalt- and nickel mines.
• Incidence was very low in the 19th century.
• Is now worldwide the commonest form of cancer in
  men, and the fifth most frequent cancer in women.

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Cause and effect cigarette smoking ? lung cancer

• Men started smoking cigarettes in 1920s ? 20
  years later, incidence of lung cancer in men
  climbed sharply.
• In 1940s, women became cigarette smokers ? 20
  years later, a similar dramatic increase in lung
  cancer among women.

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Risk factors

• 1. Tobacco (and passive) smoking
• 2. Air pollution in urban areas
• 3. Chronic conditions COPD
• 4. Occupational exposure (man-made
• mineral fibre)

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Genetic factors

• Aryl-hydrocarbon-hydroxlase system (AHH) converts
  weak carcinogens in cigarette smoke into active
  carcinogens

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Prevention of lung cancer

• 80 of lung cancer cases are associated with many
  years of tobacco smoking, and can therefore be
  AVOIDED.

• 10 of lung cancer cases are associated with
  exposure to occupational carcinogens, and can
  therefore be AVOIDED.

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Histological types of lung cancer

• 2 major types
• small-cell lung cancer, and
• nonsmall-cell lung cancer, which is further
• subdivided into
• squamous cell carcinoma,
• adenocarcinoma, and
• large-cell carcinoma.

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Origin and characteristics of various types of
lung cancer

• Squamous cell lung cancer commonest type in
  males, central origin, manifests early
• Adenocarcinoma commonest type in females,
  peripheral origin, manifests late
• Large cell lung cancer least common type,
  peripheral origin
• Small cell lung cancer most aggressive type,
  central origin, spreads quickly

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Snap Lung Cancer
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Histological distribution of lung cancer depends
on age and sex

• In males 35 75 years
• Squamous cell carcinoma
• Small cell cancer
• Adenocarcinoma
• Large cell cancer

• In females 35 75 years
• Adenocarcinoma
• Small cell cancer
• Squamous cell carcinoma
• Large cell cancer

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Biology of lung cancer

• Oncogenic event ? pluripotent cell
• ?
• small cell lung cancer
• large cell lung cancer
• squamous cell lung cancer
• adenocarcinoma
• Souhami

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Histological diversity of lung cancer (SCLC)

• Pluripotent cell or stem cell can differentiate
  into
• Small cell lung cancer
• classical cell line (70)
• variant cell line (30)

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Histological diversity of lung cancer (NSCLC)

• Pluripotent cell or stem cell can differentiate
  into
• Non-small cell lung cancer
• Squamous cell lung cancer
• Non-squamous cell lung cancer

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Early detection of lung cancer

• High mortality rate is related to low cure rate
  (13)
• Low cure rate is related to lack of early
  detection measures
• Past screening measures annual chest x-rays,
  quarterly sputum cytology have not been
  successful
• Biologic and genetic features offer new
  possibilities

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Prevention of lung cancer

• Primary prevention
• 85 87 of lung cancers are caused by
  
• tobacco smoking
• Secondary prevention
• Diet and vitamin consumtion may play a role.
• Prevention strategies based on genetic and
  biologic changes
• Replacement of missing suppressor genes?

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Conclusions

• No currently established means for the screening
  or early detection of lung cancer
• 85-88 of all lung cancers are caused by active
  or passive exposure to tobacco smoke
• Reduction of tobacco consumption still is the
  most important strategy

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Recommended literature

• Doll, Peto et al. Mortality in relation to
  smoking 20 years observation on male British
  doctors. Br. Med. J., 1976 (2) pp 1525-1536.
• Law MR. Genetic predisposition to lung cancer.
  Br J Cancer 1990 (61) 195-206.
• Carney DN. The biology of lung cancer. Current
  topics in lung cancer 1991, pp 3-14.

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More Information on the WWW

• CancerNet Statistical Data Sources
• UICC GLOBALink
• Institute of Epidemiology
• Department of Epidemiology Links
• SEER Cancer Statistics Review, 1973-1996
• Cancer Epidemiology, Biomarkers Prevention Table
  of Contents
• Lecture Link Application
• Todays??-Smoking and Kreyberg Lung Tumors
• What if I smoke cigarettes?