10/16/2015C.R. Apap1 Lung cancer: a preventable disease Epidemiology addresses issues related to ...
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Transcript of 10/16/2015C.R. Apap1 Lung cancer: a preventable disease Epidemiology addresses issues related to ...
04/20/23 C.R. Apap 1
Lung cancer: a preventable disease
Epidemiology addresses issues related to
Heredity,Life-style, andEnvironment.
04/20/23 C.R. Apap 2
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.
04/20/23 C.R. Apap 3
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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Yearly incidence rates of lung cancer
0
20
40
60
80
100
120
140
Males Females
Sex distribution
Yea
rly
Inci
denc
e pe
r 10
0.00
0
Maoris in New Zealand
American blacks in San Francisco Bay Area
Inhabitants of West Scotland
Belgium
India
African populations
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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)
04/20/23 C.R. Apap 6
Genetic factors
Aryl-hydrocarbon-hydroxlase system (AHH) converts weak carcinogens in cigarette smoke into active carcinogens
04/20/23 C.R. Apap 7
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.
04/20/23 C.R. Apap 9
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
04/20/23 C.R. Apap 10
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 cancerAdenocarcinomaLarge cell cancer
In females 35 – 75 years:
AdenocarcinomaSmall cell cancerSquamous cell
carcinomaLarge 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
04/20/23 C.R. Apap 15
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
04/20/23 C.R. Apap 16
Prevention of lung cancer
Primary prevention85 – 87% of lung cancers are caused by tobacco smoking Secondary preventionDiet and vitamin consumtion may play a role. Prevention strategies based on genetic and
biologic changes Replacement of missing suppressor genes?
04/20/23 C.R. Apap 17
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 Today’s??-Smoking and Kreyberg Lung Tumors What if I smoke cigarettes?