Presentation on theme: "Epidemiology of Cancer (Environmental Biology of Cancer) Folder Title: Epidemio Updated: January 29, 2013 EpiTitle."— Presentation transcript:
Epidemiology of Cancer (Environmental Biology of Cancer) Folder Title: Epidemio Updated: January 29, 2013 EpiTitle
Epidemiology of Diseases Distribution of patterns of health and disease. Determination of potential causation that leads to the observed distribution. Observational vs Experimental Sciences: Observe episodes of disease appearance (e.g. geographic "hot- spots" or occupational or familial patterns) Retrospective analysis of potential causative associations Prospective trials to determine causative sources Determine "Relative Risk" or "Odds Ratio" Small vs large Relative Risk Values Association or Correlation is not Causation
Complications in Epidemiological Observations Reliable reproducible data and conclusions vs. firmly held beliefs or "common sense" assumptions. Problems with acquisition of data and data reliability: Time patterns of exposure vs appearance of disease Combinations of causative sources and sequences of exposures High background appearance (non-rare diseases) Usually small impact of an agent on an individual or population Retrospective data: recall bias and data reporting Prospective trials: Costs, ethical problems, subject cooperation Deducing Actual Causation from Epidemiological Data
Epidemiological data comparing high and low incidence rates based on different population groups poses the questions: 1.Why is one group presenting high risk for a given type of cancer? 2.Why is another group presenting relatively low risk for that type of cancer? 3.What does that tell us about causation? 4.Does that present possibilities for prevention and diagnosis?
Epidemiological data comparing high and low incidence rates based for different types of cancer based on different countries poses the questions: 1.Why is a given cancer (e.g. liver cancer) high in one set of countries? 2.Why is that same cancer very low in other countries? 3.What does that tell us about causation? 4.Does that present possibilities for prevention and diagnosis?
Please respond to this question as a fill-in-the-blank question using the directions provided in the hand-outs. Liver cancer is greatly elevated in Hong Kong and in other places in South East Asia. This is due to 0 of 100
There is elevated risk of breast cancer depending on whether a woman has had a baby or not, and depending on how many babies she has had. What does this suggest as a plausible response to reduce the risk of death from breast cancer? 1.Get pregnant as often as possible. 2.Monitor and control hormonal status. 3.Deny the evidence and don’t worry about it. 4.Eat a low fat diet. 5.Monitor the high risk group more stringently than the lower risk group. 6.Carry out ovariectomy as early in adult life as possible. 0 of 100
Epidemiological Data can also sometimes provide clues about the biological mechanisms underlying certain types of cancers. Malignant Melanoma (Solar radiation exposure) Burkitt’s Lymphoma (Co-infection with virus transmitted by mosquitos also transmitting malaria)
Lifetime Melanoma Risk: 1935 to 1996 Figure 7-8, Biological Basis of Cancer, 1998, p 194 MelRisk
White Males White Females Black Males & Females MelRace
Reciprocal translocation between chromosomes 9 and 22 produces fusion of a cancer-inducing gene, the abelson or abl gene with information on another chromosome and gives fusion protein involving the abl gene product that is mis- expressed and drives cell division in leucocytes leading to chronic myelogenous leukemia.
Burkitt’s Lymphoma is Associated with co-infection with a virus carried by mosquitos. This is because the virus: 1.Causes point mutations 2.Activates antibody synthesis 3.Turns off a cancer suppressor gene 4.Induces a high fever 5.Secretes a potent chemical carcinogen 0 of 100
What is this slide showing? (Short answer question) 0 of 100
See Figure 11.1, Cancer incidence at various ages for men and women. p. 400. Weinberg. Note maximum incidence per 100,000 population at about age 70, then drop off after that age. Serious incidence begins around age 35 except for breast cancer which can have an earlier onset depending on genetics. Incidence of Various Kinds of Cancers in Men and Women as a Function of Age
Cancer in children and younger adults has an incidence rate of 11% of the total cancers, but accounts for only 5% of the total cancer deaths. Why is that the case? What does that difference between incidence and mortality tell us about cancers in younger persons? (This is a fill-in-the-blank question. Keep it brief. You can use abbreviations if they are clear). 0 of 100
Specific Cancer Incidence and Migratory Patterns: Cancers and Environmental Effects
See also Figure 7-6, Biological Basis of Cancer, p 191 EatFat
(When this slide opens you do not have to send in your name under “Send User Data” unless you borrowed a Response Card from us this morning. If you borrowed a Card be sure to remove the previous name and enter your names. The two previous slides show patterns of cancer incidence within one or two generations in populations of persons who have migrated. What do these data tell us about causation of these cancers? You can abbreviate as long as I reasonably can figure out your meaning. 0 of 100
Detailed analysis of the epidemiology of cancers is important in cancer medicine because it helps us to understand __ ___ ___ ___ ___ ___ (or to) __ __ __ __ __ __ __ some cancers You only need one response 0 of 100
Cancer in children 0 to 14 years of age occurs in 15 per 100,000 as the incidence rate. Cancers in that same group accounts for 2.5 deaths per 100,000. What does that tell us about cancers that affect children ages 0 to 14? (This is a fill-in-the-blank question. Keep it brief. You can use abbreviations if they are clear). 0 of 100
Understanding the epidemiology of cancers allows us not only to understand the causes of some cancers but also helps us to design programs for the _ _ _ _ _ _ _ _ _ _ of some cancers. One word only! 0 of 100