Breast Cancer Screening: A Primary Care Perspective Flashcards
Screenings, by definition, are only in people without ______________.
symptoms; if they have symptoms, that is a diagnostic test
What happens to early-stage incidence and late-stage incidence when screening protocols are implemented?
Early-stage incidence increases and late-stage incidence decreases.
Breaking down cancers into very fast, fast, slow, and very slow progressors, what cancers are you hoping to find with screening?
Fast
Note: Over-diagnosis occurs in the slow and very slow cancers (like prostate cancer) and screening is unlikely to catch the very fast progressors (like melanoma).
What is lead-time bias?
If you discover something earlier then it appears that people in the screened group live longer.
What is length-time bias?
You’re more likely to discover something that’s slow growing.
In a 2x2 table, the _____________ is on top.
positive (those who have the disease)
Why is high sensitivity important in a screening test?
High sensitivity means you have few false negatives, which is important if you’re going to tell people they don’t have a disease.
What is the SpIn mnemonic?
With a highly SPecific test, you’ve ruled the patient IN. This is so because with high specificity you have few false positives.
What is the formula for NPV?
(TN) / (TN + FN)
What is the likelihood that a woman with an abnormal mammogram has breast cancer?
6.6%
As the prevalence of a certain disease goes down, the rate of ______________ goes up.
false positives
What is the prevalence of breast cancer in women in their 40s and 50s?
40s: 1%
50s: 2%
What is the likelihood ratio?
(probability of test result in person with disease)
_____________________________________
(probability of same result in person without disease)
What are good LRs for ruling something in and out?
In: greater than 10
Out: less than 0.1
What are the formulae for LR + and LR -?
LR +:
(sensitivity) / (1 –specificity)
LR –:
(1 –sensitivity) / (specificity)
The relative risk reduction is equal to _____________.
1 –(relative risk)
How many women in their 40s need to be screened to save one life from breast cancer?
3,334
MRI is recommended for women whose lifetime risk of developing breast cancer is _____________.
greater than 20%
Tamoxifen is recommended for women whose 5-year risk of developing breast cancer is _________.
greater than 3%
The number needed to treat decreases as ______________ increases.
prevalence
