18 Cancer Screening and Prevention

Question 1

What is screening?

Answer 1

the investigation of asymptomatic people in order to slassify them as likely or unlikely to have the disease

Question 2

What are the 10 WHO essential prerequisites for screening?

Answer 2

public heatlh problem
accepted treatment
diagnostic/treatment facilities
recognised latent phase
suitable test/examinationtest acceptable to target population
natural history understood
agreed treatment policy
cost economially balanced
continuous case-funding

Question 3

What characteristic of a disease make it suitable for screening?

Answer 3

common
severe consequences
presymptomatic phase undiagnosed but detectable
early treatment must offer advantage
evidence of net benefit

Question 4

Name 2 types of bias explored inthis lecture

Answer 4

lead time bias

length bias

Question 5

What is the principle of lead time bias?

Answer 5

by bringing forward the day of diagnosis, the length of time between diagnosis and death is increased by the lead time

Question 6

What is length time bias based on?

Answer 6

the fact that diseaes which lend themselves to be identified by screening are more likely to be indolent and less aggresive conditions

Question 7

what are the 3 cancer screening programmes in England?

Answer 7

Breast
Cervical
Bowel

Question 8

Why are mammography sensitivity values lower for younger women?

Answer 8

they have denser breast tissue so an MRI might be needed to detect cancers

Question 9

Why does PPV between first and second mammography screens differ?

Answer 9

anomalies are detected in the first screen which are eliminated

Question 10

What is the NHSBSP?

Answer 10

NHS Breast Screening Programme

Question 11

Which women are screened for breast cancer and how often?

Answer 11

50-70 are invited every 3 years (>70s can request appointment)

changing to 47-73

Question 12

What is the NHSBSP annual budget?

Answer 12

£75 million

£45-50 per woman

Question 13

What are the criticisms of NHSBSP?

Answer 13

identifying DCIS is overdiagnosis of breast cancer, as they never progress and threaten a woman’s life

Question 14

What proportion of screen detected cancers are DCIS?

Answer 14

20%

Question 15

What is DCIS?

Answer 15

ductal carcinoma in situ

Question 16

What proportion of those ‘called back’ following screening have cancer?

Answer 16

14%

Question 17

What measure do we use to decide whether is should be lumpectomy or mastectomy?

Why is this problematic?

Answer 17

grade

this is unsatisfactory for predicting the future behaviour grade, so many women

Question 18

for each death prevented by breast screening, how many women receive unnecessary treatment?

Answer 18

3

Question 19

How does the likelihood of ever receiving a mammogram change with age?

Answer 19

it doesn’t really

Question 20

What factors are significant for predicting the likelihood of a woman ever having a mammogram?

Answer 20

number of cars
house ownership status

note that for screening, there is no relationship to education class, ethnicity, or region

Question 21

According to the independent review of adult screening programmes in england october 2019, what could be done in increase uptake in programmes?

Answer 21

test reminders
social media campaigns
good practice on physical and learning disabilities
encouraging links with cultural leaders to reduce health inequalities
increase awareness of diversity issues
consider financial incentives to promote out of hours/weekend appointments

Question 22

What are te 3 potentia screening tests available for prostate cacner?

Answer 22

Digital Rectal Examination
Transrectal US
Prostate Specific Antigen (PSA)

Question 23

What proportion of men with elevated PSA will not have prostate cancer?

Answer 23

2/3

Question 24

What are the problems wth PSA testing?

Answer 24

unreliable across different labs
poorly understood natural history
patients receive unnecessary treatment with serious side-efects
15%
2/3

Question 25

What percentage of men with normal PSA in testing will have prostate cancer?

Answer 25

15%