Deck 15: Early Detection: What Benefits at What Cost

Question 1

Potential harms from being screened include (select all that apply):

A)Complications arising from follow‐up investigation of persons who screen positive
B)Unnecessary treatment of persons with true‐positive test results who have inconsequential disease
C)Costs and inconvenience incurred during investigations and treatment
D)Anxiety generated by the investigations and treatment
E)All of the above

Answer 1

All of the above

Question 2

Which of the following conditions need to be met before a population‐based screening programme could be considered as a planning priority? (Select all that apply)

A)An accurate, cheap and safe screening test for the disease is available
B)Strong support from the peak doctors' association
C)The disease has severe consequences and is common in older people
D)RCTs have shown that lives are saved by the screening programme
E)All of the above

Answer 2

An accurate, cheap and safe screening test for the disease is available
The disease has severe consequences and is common in older people
RCTs have shown that lives are saved by the screening programme

Question 3

Which of the following types of study have led to the introduction of a population‐ based screening programme for the cancer in question?

A)Randomised trials of prostate cancer screening
B)A cross‐sectional study of mammography accuracy
C)Case‐control studies of mammography and breast cancer deaths
D)Randomised trials of 'Pap' smears for cancer of the cervix
E)Descriptive studies of mortality trends for colorectal cancer (CRC)
F)Noneoftheabove

Answer 3

Noneoftheabove

Question 4

Which of the following activities should be part of a public health cancer screening programme? (Select all that apply)

A)Opportunistic testing for cancer by GPs
B)Monitoring of cancer death rates before and after the screening programme starts
C)Population‐wide invitations to attend screening
D)Good facilities in place for following up those who screen positive
E)More advanced screening tests for those who can afford them

Question 5

Which of the following statements about screening tests are correct? (Select all that apply)

A)The sensitivity of a test is the proportion of all persons who have the disease who test positive
B)The predictive value of a negative test (or negative predictive value, NPV) is not affected by the sensitivity of the test
C)The prevalence of the disease of interest does not affect the accuracy of a screening test
D)The prevalence of the disease of interest does not affect the performance of a screening test
E)The specificity of a test is the proportion of all those who do not have the disease who test positive
F)Across‐sectionalsurveyisthebeststudydesigntoassesstestaccuracy

Question 6

Which of the factors listed below are desirable features of a screening test? (Select all that apply)

A)Painless
B)Socially acceptable
C)Medically innovative
D)High positive predictive value
E)Low specificity

Question 7

Which of the following characteristics of a disease make it potentially suitable as the target of a screening programme? (Select all that apply)

A)It is rare in the population
B)People are very afraid of getting this disease
C)Outcomes are better if the disease is treated early in its natural history
D)Patients do very well on standard treatment whenever they are diagnosed
E)There is a very good but expensive test available to diagnose it

Question 8

Use the data in the following table to identify which of the following statements are true.(Select all that are true).

A)Prevalence = 10.2%
B)Sensitivity = 81.9%
C)Specificity = 4.4%
D)Specificity = 98.1%
E)Positive predictive value (PPV) = 65.6%
F)Negativepredictivevalue(NPV)=98.1%

Question 9

About 20% of men who come to autopsy have a cancer in their prostate gland which had not been diagnosed while they were alive, i.e.they did not have clinically‐evident
Prostate cancer.However, as a result of this undiagnosed cancer they will have had
Increased blood levels of prostate‐specific antigen (PSA) while they were alive, and
This is what screening tests for prostate cancer detect.Given this, if a population‐
Based screening programme to detect prostate cancer is introduced, which of the
Following statements are correct? (Select all that apply)

A)There is likely to be a high rate of false positive tests for clinical prostate cancer
B)The incidence rate of prostate cancer will increase
C)The mortality rate of prostate cancer will fall
D)All of the above
E)A and B are both correct

Question 10

Use the graph below to identify which of the statements below are correct.(Note that the UK breast cancer screening programme began in 1988.) (Select all that apply) Age‐standardised breast cancer mortality rates in the UK, 1971‐2012 (From Cancer
Research UK - Breast cancer mortality statistics;
Http://www.cancerresearchuk.org/health‐professional/cancer‐statistics/statistics‐
By‐cancer‐type/breast‐cancer/mortality#heading‐Two accessed October 8, 2015.

A)It is clear from this graph that the introduction of breast cancer screening into the UK has led to a consequent decline in deaths from breast cancer
B)Using simple descriptive data like those in this figure is too crude to be a useful way to assess whether the screening programme is working
C)The graph can be described as follows: "This figure shows the trends in the annual age‐standardised mortality rate for breast cancer in the UK between 1971 and 2012.
From a level of ~37 deaths per 100,000 women in 1971 the rate rose steadily to
About 1984 where it peaked at around 42, remaining fairly stable for 5 years before
Starting a steady decline; this slowed slightly after about a decade, to reach a rate of
~24÷100,000 in 2012"
D)Without seeing overall mortality trends the graph cannot be interpreted correctly
E)If we knew the incidence rates of breast cancer over the same period we could fully interpret the mortality data to decide if the screening programme was responsible
For the improvements over the past 2 decades