Cancer epidemiology

Question 1

What is the definition of cancer epidemiology?

Answer 1

The study of the distribution/patterns and determinants of the likelihood of cancer development. Cancer epidemiology can be used to identify events that increase or decrease cancer incidence in specific populations

Question 2

What is incidence?

Answer 2

Occurrence of a given medical condition in a specified population within a specified time period

Question 3

What is prevalence?

Answer 3

The total number of cases of a given disease in a specified population at a designated time

Question 4

What is mortality?

Answer 4

Measure of the number of deaths in a particular population, scaled to the size of that population, per unit of time

Question 5

What are risk factors?

Answer 5

Something that increases a person’s chances of developing a disease

Question 6

What is correlation?

Answer 6

A statistical relationship between two variables

Question 7

What is causation?

Answer 7

Establishing the cause of a disease

Question 8

What are co-variates?

Answer 8

An independent variable that can influence the outcome of a given statistical trial, but which is not of direct interest

Question 9

Why is cancer epidemiology important?

Answer 9

• Provides an overview of cancer burden and its likely future evolution
• Describes national/international differences in cancers over time & possible reasons
• Investigates predictors of survival
• Assesses efficacy of preventive measures

Question 10

Which gender is more affected by cancer?

Answer 10

Males by 21% compare to females at 18%

Question 11

What are the 3 most common cancers in the world?

Answer 11

1. Lung
2. Breast
3. Colorectum

Question 12

What are the major risk factors for cancer?

Answer 12

• Aging
• Lifestyle (tobacco, alcohol, poor diet, lack of physical activity, overweight, etc.)
• Environmental (sunlight, infectious diseases, pollution, etc.)
• Genetics (family history of cancer, sporadic mutations, etc.)
• Occupational carcinogens
• Radiation

Question 13

What is the biggest risk factor for cancer?

Answer 13

Aging

Question 14

How to study cancer epidemiology: correlation or causation?

Answer 14

Correlation is not causation!

Ice cream sales can be correlated to shark attacks but it is not the cause!

Question 15

What is descriptive epidemiology studies?

Answer 15

To describe the difference in occurrence of a particular cancer between different groups (age, gender, country, a period of time for time trend) and to generate hypotheses for increased/decreased incidence for the specific tumour type

Question 16

What is analytic epidemiology studies?

Answer 16

To study risk factors or potential causes of cancer by a particular study design (case-control study or cohort study)

Question 17

What is intervention studies?

Answer 17

Applying the knowledge (risk/protective factors) obtained from analytic epidemiological studies to specific population in order to reduce the risk of cancer

Question 18

What are examples in the study design for descriptive and analytic studies?

Answer 18

Descriptive studies: case series, case report or descriptive statistics

Analytic studies: cohort study, case-control study, before-after study, etc.

Question 19

What is Randomised Controlled Trials (RCTs), what does it provide and when is it not possible?

Answer 19

• A design with subjects randomly assigned to “treatment” and “comparison” groups
• Provides most convincing evidence of relationship between exposure and effect
• Not possible to use RCTs to test effects of exposures that are expected to be harmful, for ethical reasons

RCT is the “gold standard” of research designs and provides most convincing evidence of relationship between exposure and effect