epidemiology of cancer Flashcards
what did cristian tomasetti and bert volelstein say in an article
-some tissue types give rise to human cancer million times more often than any other tissues
-only a third of the variation in cancer risk among tissues is attribuable to enviromental factors and inherited dispositions
-basically a majority of cancers are due to bad luck arising during dna rep
what was the reaction of epidemiologists after berts claim
-they were like bro wtf
-the epidemiologists said that the claim was wrong
-cancer rates change over time
-a majority of cancers are preventable
true or false cancer rates are changing over time
-true
-different cancers in different tissues change over time
what was the data that bert was looking at when he made his claim
-he was looking at the r^2 value of 0.65
-a linear corrolation of 0.804 suggests that 65% of the differences in cancer risk between different tissues can be explained by the total number of stem cell divisions in those tissues
why was berts data kinda ass
-because his 65% of the differences in cancer risk between different tissues can be explained by the total number of stem cell divisions
-it can’t explain the differences in cancer risk between different people and between different populations
-does not explain hy colorectal cancer is so mugh higher in canada compared to other countries
what is epidemiology
study of patterns and causes of disease in a population
what does cancer surveillance in epi mean
-measures burden of disease, incidence and mortality trends
-who gets cancer
-how many get cancer
how many will die
-is the risk of getting cancer increasinf or decreasing
what does cancer risk mean in epi
assessing candidate etiologic factors
what does cancer prevention mean in epi
assessing the efficacy and the impact of screening, chemoprevention and other preventive approaches
what does cancer survival mean in epi
assessing prognostic factors and determinants of quality of life
what are the 4 main things that people in epi study
-cancer surveillance
-cancer risk
-cancer prevention
-cancer survival
measuring occurrence of cancer: number of cases
-new cancer cases
-new cancer deaths
-units: cases
-number of cases are useful for health system planning like how many beds you need in a hospital
What does incidence rate;
new cancer cases in a population per person years
what is the mortality rate
new cancer deaths in a population per person years
what are the units in epi
cases per person time
unlike number of cases, rates account for….
population size and time frame and so are useful for measuring risk and causality
why is the rate of cancer in 85ys old high than 60 years olds
because there are more 65 years olds but there are less 85yrs old. but there are more 85yrs old that have cancer
true or false; incidence rate of cancer is higher in high income countries
true
why is the rate of incidence is higher in high income countries
-better diagnosis in high income countries
-our heaqlth systems are better which help us escape easier deaths
what census is used in direct afe standardization
-2011 census population in canada (cross-time comparisons)
-1960 world population (cross-country comparisons)
what happens after direct age standardization
-all populations have the same standard age distribution
-any difference are not caused by age, basically everyone is 40
why is direct age standardization kind of a slay
allows comparing populations with different age structures (countries, time periods) to assess changes in cancer risk
what is crude incidence rate
dividing by population size adjusts for changes in pop size
is your risk of cancer increasing over time
it is decreasing
true or false: age standardized incidence rates in canadians are getting lower
-false, they are kinda equals out
-some are getting lower and some are getting higher
do we survive more
yeah we do
-that is due to less lung, colorectal and best cancer mortality
what are the odds to get cancer as a man and a woman
-44% in men
-43% in woman
what are the odds to die from cancer as a man and a woman
-26% in men
-22% in women
net cancer survival adjusts for….
competing causes of death
which is when people had cancer and they still end up dying
what is the rate of survuval for colorectal cancer
67%
what is the rate of survuval of prostate cancer
91%
what was the 5 year survival rate in the 40s vs now
-25%
-65%
true or false: childhood cancer incidence increased and morality decreases
true
why is the incidence rate of cervical cancer so different between southern afrika and australia
-less pap smears to detect pre cancer and cancer
-australia has more screenings
-hpv causes cervical cancer which can be prevented by protection