Epidemiology of cancer

Question 1

What is the purpose of age-standardizing cancer incidence and mortality rates?
A) To control for differences in age structure between populations
B) To control for different population sized between population
c) To control for variation in risk exposure between pop
d) to control for changes in cancer rankings over different time periods

Answer 1

A

Question 2

Which of these cancers has the lowest net 5-years age standardized cancer survival

Answer 2

Pancreas

Question 3

In the 1950s, the first studies which found an association between smoking and lung cancer were criticized because they were retrospectively measuring tobacco consumption in lung cancer cases. What type of study design was implemented to recruit and follow-up individuals prospectively to assess the risk of lung cancer in smokers and non-smokers
a) case control study
b)Intervention trial
c) cohort study
d) randomized controlled trials
E) case reports of lung cancer in smokers

Answer 3

Cohort study

Question 4

Cancer is due to bad luck… Most cited scientist said that or epidemiologists?

Answer 4

Most cited scientist (Vegelstein)

Question 5

True or False : A very strong correlation exists between the number of stem cell pourcentage and lifetime risk of cancer in the same tissue

Answer 5

True

Question 6

True or False : We can explain difference in cancer risk between different people and between different population

Answer 6

False = Cannot!!!

Question 7

A study of patterns and causes of disease in a population

Answer 7

Epidemiology

Question 8

A burden of disease, incidence and mortality trends, who gets cancer, how many people have cancer, how many people wil get cancer

Answer 8

Cancer surveillance

Question 9

Why is there more cancer cases between 65-69 years olds than 85-89 years old? However we know thatg incidence rate increase with age… how?

Answer 9

Theres more population that are 65 years old than 85… they often die, so we report more cases at 65.

Question 10

Why is incidence rate higher in higher income countries

Answer 10

we live longer, people die for other reasons, better diagnosis, people in higher income countries are middle aged and in low income countries people are younger

Question 11

True or false: After standardization: all populations have the same standard age distribution and it allows comparing population with different age structure to asses changes in cancer risk

Answer 11

True

Question 12

Why is the incidence rate of childhood cancer increasing?

Answer 12

Better diagnosis, childhood cancer are rare, so theyre hard to study

Question 13

Why is the incidence rate for cervical cancer so high in Southern Africa compared to New Zealand, but we say its preventable?

Answer 13

HPV cases in southern africa in higher, and low screening

Question 14

Why is the incidence rate for liver cancer higher in mongolia and egypt compares to nepal?

Answer 14

Hepatitis B & C because of reused syringes and also Alcohol (muslim countries)

Question 15

True or false: Cancer occurs during time

Answer 15

True, theres a latency period between the time someone starts smoking and cancer

Question 16

Why did Stomach cancer decrease in Males during the years significantly?

Answer 16

We stopped using salt to conserve food, and helicobacter causes ulcers

Question 17

What increased the tobacco consumption with time…(2 events)

Answer 17

1- First War
2- War impact few years later

Question 18

How did tobacco consumption decrease? whhy?

Answer 18

Great depression

Question 19

Oschner stated that lung cancer and smoking was related… who wasnt ok with that theory?

Answer 19

Graham

Question 20

Clinical trial as a study type is Exposed VS unexposed… why couldnt we use it in Smoking/lung cancer

Answer 20

Ethics! you can make people smoke just for an experiment
Expensive, limited number of comparison

Question 21

What question do you ask yourself in a hypothetical scenario for counterfactuals?

Answer 21

If you go back in time and ask yourself is the risk factor wasnt there, would you still get cancer?

Question 22

Whats a Case control study

Answer 22

Cases Vs Controls …. so you compare individuals who have the outcome with individuals who dont have the outcome (controls)…

Question 23

RR =relative risk
Above +1

Answer 23

exposition give higher risk to the disease

Question 24

RR = 1

Answer 24

Same risk same outcome

Question 25

RR <1

Answer 25

Protective effect, lower risk to have outcome (cancer)

Question 26

Case control example

Answer 26

Studied cases in hospitals of 600 men with lung cancer and 700 men without lung cancer with the same age and economic distribution

Question 27

Cohort study is…

Answer 27

Start with a healthy population and follow them during time, the ones who smoke and the ones who didnt (with a questionnaire from the start)

Question 28

Whats the problem with cohort studies?

Answer 28

Not randomized (we dont know if some smokers live in worst conditions than others)

Question 29

Whats Confounding bias in observational data? Example?

Answer 29

Coffee and cancer? Possible that the exposure could be correlated with other factors like smoking

Question 30

Whats startification?

Answer 30

Seperate groups and look at the relationship between exposure and outcome

Question 31

Information bias is an error due to incorrect measurements, give an example

Answer 31

Bacon and colorectal cancer, if yo incorrectly classify people, you’re not gonna calcultate the correct risk of cancer

Question 32

True or false: Women who have been taking aspirin for 20 years have 32% lower risk of being diagnosed with colorectal cancer

Answer 32

True

Question 33

True or False: The prevelance changes over time

Answer 33

True

Question 34

True or false: non-steroidal anti-inflammatory reduce inflammation and prevent blood clots

Answer 34

True

Question 35

Whats a PAF

Answer 35

population attributable fraction - the more RR and the more prevelance (how common is the exposure), the more PAF (more cancer cases)

Question 36

If the RR is 85% for HPV and cervical cancer… how much is PAF? (Graph)

Answer 36

100%

Question 37

Highest risk factor in canada and US

Answer 37

Smoking

Question 38

Why do we screen for colorectal cancer at a certain age?

Answer 38

Colorectal cancer is not detectable at age 40, but theres the period where its detectable (from 49 to 57)

Question 39

True or false: Antigen-125 (biomarker in blood) doesnt allow you to detect precancer ovarian cases, only ovarian cancers

Answer 39

true

Question 40

Why did we have more ovarian cancer cases diagnosed in intervention group than control 13years after the first screening?

Answer 40

False positives, screened women that had cancer without symptoms

Question 41

What does Canadian Tark Force on preventive Health care do?

Answer 41

gives advice for screening, and prevention