2. Risk Factors & Incidence Flashcards
What is a ‘cause’ of cancer?
A factor that directly changes something in the biology to result in cancer
Eg environmental exposure/ genetic susceptibility
T or F:
1. If you are exposed to a cause of cancer, you will always get the disease
2. Few cancers arise from a single cause
3. Exposures can only cause 1 cancer
- F: it is not an all or nothing relationship you can be exposed but not develop the disease.
- T
- F: some exposures can cause more than 1 cancer
What is a risk factor
An exposure than increases the risk of disease
What are some examples of:
- exposures
- outcomes
Exposures: environment, lifestyle, infections, genetics
Outcomes: defined disease, health-related event, death
What is a confounding factor? With an example
A factor associated with an exposure that is wrongly linked to an outcome
EG: alcohol (exposure), lung cancer (outcome), smoking (confounding factor)
What are the IARC carcinogenic hazards to human calissifcations
1: carcinogenic
2A: probably carcinogenic
2B: possibly carcinogenic
When measuring exposures, what may affect the type of data collection method used?
- study type
- detail of data required
- availability of existing records
- lack of/ poor recall of exposure
- sensitivity of topic
- variability of exposure over time
- availability of measurement tools
- cost
What are some examples of sources of exposure data?
- questionnaires
- diaries
- records
- biological methods
- environmental methods
What are the 2 types of questionnaires used to collect data on exposure, and what are their benefits/ drawbacks?
- self administered: + Cheap, - no quality control
- interviewer: + improve participation & completeness, - expensive, must be fair
What are some examples of data collection commonly used in cancer epidemiology?
Records/ routine data eg:
Medical records
Cancer registrations
Specialized surveillance
Death certificates
Why is population-based cancer registries often deemed superior to hospital-based?
- data is comparable between countries as many countries have a population-based registry
- you cannot calculate rates, risk, and incidence from hospital-based registries as it is more difficult to know underlying factors
- as people move around the country, hospital-based registries are less respective of the population of the area
- population- based used well defined populations
To measure cancer occurrence, what must be defined?
- case: standardized definition of disease
- population: eg region/ whole country?
- Time period
How do you calculate prevalence
No. Of cases in defined population at one time
/
No. Of people in defined population at the same point in time
What is prevalence and what is it dependent on?
It is a ‘snapshot’ of disease frequency (a proportion)
It is dependent on: incidence (new cases), survival/mortality, recurrence, recovery/cure
Using the bath tub analogy, describe incidence, prevalence, cure, mortality, and recurrence
Prevalence is how full the bath tub is at one time
Incidence is the flow of water into the bath tub, the new cases
Cure/mortality is the leak of water from the bath tub
Reccurance is the water returning to the tub
