Flashcards in Cancer Data- L11 Deck (18)
What are the differences between mortality, incidence and prevalence ?
mortality= death due to cancer - smallest number
incidence = number of new cases - diagnosis = more than mortality numbers
prevalence- all cases- more than incidence number
What was shown between lung cancer and cigarette consumption ?
the link between smoking and developing lung cancer is very similar demonstrating a very strong correlation
also there is a 20 year lag between smoking and cancer so it takes a long time to appear
Why are death rates for lung cancer in men declining but not in women ?
because originally men use to smoke more than women but nowadays men have been more readily giving up smoking compared to women
women may have less inclination to give up due to the pull in lower body weight caused by smoking
Are cancer rates increasing or decreasing ?
- diagnosis is getting better and early screening methods are helping
certain cancers such as lung, prostate and stomach are declining
If cancer rates are declining what does this indicate ?
it indicates that there is measures that you can take to reduce your likelihood of developing cancer therefore cancer is not inevitable
Why have the rates of stomach cancer been declining ?
intervention of fridges enabling less preservative in food and less consumption of salted, pickled and smoked foods
eating more fresh food
Even though the us declared war on cancer what happened?
in 1970= 331000 deaths
in 1996= 555000 deaths
30% of these deaths are due to smoking
1950- 193.9 per 100,000 us people
2002- 193.4 per 100,000 us people
2005- 183.8 per 100,000 us people
not really any difference
What do all of the cancer experts agree on about cancer?
they key to treating cancer is catching it early
Why have the death rates for heart disease declined substantially between 1950-2000 yet cancer hasn't ?
it is thought that heart disease has substantially declined because we are better at accepting the risk factors associated with it and doing something about it
its difficult with cancer to determine the precise risk factors for the disease
Why do cancer rates vary between countries?
because of different environmental exposures
for example there is greater skin cancer rates in australia compared to japan because there is more sunlight so more uv radiation
What are the difference in cancers for chinese people living in different countries ?
prostate- minimal rates in china but when they move to hawaii or usa their rates increase
breast- much higher rates in hawaii and usa compared to china
stomach- much higher rates in china compared to hawaii and usa
What were the best estimates and range estimates for different factors contributing to cancer ?
Tobacco- BE= 30 and R= 25-40
Diet- BE= 35 and R=10-70 - lots of cancers are attributable to diet
alcohol- BE= 3 and R= 2-4
In developed countries what % of cancers are attributable to diet?
What are non-genetic factors in human carcinogenesis?
Environment - occupational exposure, sunlight, radiation
Diet - high fat
life style - exercise and caloric intake
What is necessary to justify a factor as being a human carcinogen?
it needs to have a plausible mechanism
- epidemiological and animal studies are not sufficient
How do we know that certain factors are associated with cancer?
INITIALLY- national and regional food consumption patterns and cancer rates, changing rates of cancer in migrating populations going from one dietary culture to another
SUBSEQUENTLY- case-control studies of dietary habit of cancer patients compared to controls, prospective studies with known dietary habits
THEN- animal experiments and human cell culture studies
Why are cell lines useful?
- elucidations of mechanisms
- evaluate genetic interactions