Screening Flashcards
Screening
Testing (i.e. questions, physical exams, labs etc.) asymptomatic
people
Examples of Screening
“Annual physical”
Periodic:
* Colonoscopies
* Gynecological exams
* Mammograms
* PSA
Purpose of Screening
Detect diseases that are better treated before signs and
symptoms show up and prevent people from suffering with or
dying from them
* E.g. (in theory) PSA for prostate cancer
Use knowledge of risk factors for disease to prevent or
decrease the burden of the disease by modifying the risk factors
* E.g. lipid panels for cardiovascular disease
For the best results, the disease should be:
A significant public health problem (common and/or significant
morbidity and/or mortality)
Treatable with these stipulations:
- the potential for cure increases with early detection and treatment is easily available
For the best results, the test should be..
- sensitive to pre-clinical disease
- SAFE
- inexpensive
- easily accessbile
- lead to demonstrated improved health outcomes
a condition detected by screening that does not require treatment because it will not adversely affect the patient’s life.
pseudo disease
If treated, patient may be considered “cured” despite the fact that even if untreated, the condition would not have killed them before they died of something else.
conditions that might not progress to symptomatic disease
and may even regress.
Type 1 pseudo disease
slowly progressive disease (conditions with a long detectable preclinical phase). Patient would “die with it, not from it”
Type II pseudo disease
- PROSTATE CANCER OFTEN
Unlike when a patient arrives with a concern, screening applies tests
to ostensibly healthy people. What is the pre-test probability?
VERY LOW
Harms of Screening
- harms of test (radiation, colonoscopy, cost, time)
False positives:
- psychological burden
- further testing (over-testing)
- over-treatment (even “safe” treatments impose a burden, financial and otherwise)
Thyroid cancer incidence increased 6.4X during this period
95% of these cancers were small and detected mainly
through the screening program
Mortality from thyroid cancer remained unchanged
What criteria did this program fail to fulfill?
- the potential for cure apparently did NOT increase with early detection
- testing did NOT lead to demonstrated improved health outcomes
Screening means testing people for conditions when they are
___________
asymptomatic
The goal of screening is to prevent disease or treat it early to…
to minimize disease harms
Advantages of screening include
disease prevention and early treatment.
Disadvantages include
over-testing and over-treatment
