PUBH 6035 Module 6 Quiz; Check Your Knowledge

1. Question: The main purpose of screening is to identify symptomatic disease using tests, exams, or other procedures 2. Question: The detectable preclinical phase of a disease starts when the disease can be identified by a screening test and ends when the disease produces symptoms 3. Question: Diseasesthatareappropriateforscreening… 4. Question: Usethefollowinginformationtoanswerquestions4-8.Supposethat50,000womenwhohaveneverhadabreastcancerdiagnosisareavailableandwillingtoparticipateinanew screening program of computerized digital mammography. 1132 women had apositive screening test. All of these positive women had a breast biopsy and 136 werediagnosedwithbreastcancer.Ofthe48,868whoscreened“negative”onthetest,24werein fact in the detectable pre-clinical phase. This was determined by following these womenand observing that all 24 were diagnosed with breast cancer within one year of thescreeningtest.What is the prevalence of the detectable pre-clinical phase of breast cancer in thispopulation? 5. Question: Usethefollowinginformationtoanswerquestions4-8.Supposethat50,000womenwhohaveneverhadabreastcancerdiagnosisareavailableandwillingtoparticipateinanew screening program of computerized digital mammography. 1132 women had apositive screening test. All of these positive women had a breast biopsy and 136 werediagnosedwithbreastcancer.Ofthe48,868whoscreened“negative”onthetest,24werein fact in the detectable pre-clinical phase. This was determined by following these womenand observing that all 24 were diagnosed with breast cancer within one year of thescreeningtest. Whatisthesensitivityofthisnewscreeningtest 6. Question: Usethefollowinginformationtoanswerquestions4-8. Supposethat50,000womenwhohaveneverhadabreastcancerdiagnosisareavailableandwillingtoparticipateina newscreening program ofcomputerizeddigitalmammography. 1132womenhada positivescreeningtest.Allofthesepositivewomenhadabreastbiopsyand136werediagnosedwithbreastcancer.Ofthe48,868whoscreened“negative”onthetest,24werein fact in the detectable pre-clinical phase. This was determined by following these womenand observingthatall24werediagnosed withbreastcancer withinone yearofthescreeningtest.Whatisthespecificityofthisnewscreeningtest? 7. Question: Usethe following informationtoanswerquestions4-8.Supposethat50,000womenwhohaveneverhadabreastcancerdiagnosisareavailableandwillingtoparticipateinanew screening program of computerized digital mammography. 1132 women had apositive screening test. All of these positive women had a breast biopsy and 136 werediagnosedwithbreastcancer.Ofthe48,868whoscreened“negative”onthetest,24werein fact in the detectable pre-clinical phase. This was determined by following these womenand observing that all 24 were diagnosed with breast cancer within one year of thescreeningtest. Whatisthe predictive valueofapositivetestresultforthisnewscreeningtest? 8. Question: Usethefollowinginformationtoanswerquestions4-Supposethat 50,000womenwhohaveneverhadabreastcancerdiagnosisareavailableandwillingtoparticipateinanew screening program of computerized digital mammography. 1132 women had apositive screening test. All of these positive women had a breast biopsy and 136 werediagnosedwithbreastcancer.Ofthe48,868whoscreened“negative”onthetest,24werein fact inthedetectable pre-clinical phase. This wasdeterminedby following thesewomenandobservingthe atall24werediagnosedwithbreastcancerwithinoneyearofthescreeningtest. A colleague in another city reports that the same screening test (with the same sensitivityand specificity) is achieving a predictive value positive of only 6%. What is the explanationforthis? 9. Question: Leadtimebiasmakes iterroneouslyappearthatsurvivalisbetterforscreenedversusunscreenedcases. 10. Question: Lengthbiasoccursbecausefastgrowingtumorsaremorelikelytobepickedupbyascreeningtestthanareslowgrowingtumors. 11. Question: Whatisthecorrectinterpretationoftheresultsofacalculationofspecificityfora screening testof97%? 12. Question:Thedifferencebetweenprimaryandsecondarypreventionofdiseaseis: 13. Question: Sensitivityreferstotheabilityofascreeningtesttoidentifycorrectlyallscreenedindividualswhohaveadisease. 14. Question: Sensitivityandspecificityofascreeningtestrefertoits: 15. Question: Ifthesamescreening testisconductedintwopopulations,onewithahighprevalenceofthediseaseandonewithalowprevalenceofthedisease,assumingthesensitivityandspecificityofthe screening testare the same,whichofthe following Statementsaboutpositivepredictivevalue(PPV)applies: