Lecture 9

Question 1

What is the primary aim of secondary prevention in cancer?

Answer 1

To detect and treat disease early to halt or slow its progression

Question 2

How does screening relate to secondary prevention?

Answer 2

Screening detects unrecognized disease in asymptomatic individuals

Question 3

Is a screening test diagnostic?

Answer 3

No, it identifies people at risk and must be followed by diagnostic testing

Question 4

Define sensitivity

Answer 4

% of people with disease who test positive. Formula: TP / (TP + FN)

Question 5

Define specificity

Answer 5

% of people without disease who test negative. Formula: TN / (TN + FP)

Question 6

What is the Positive Predictive Value (PPV)?

Answer 6

% of positive tests that are true positives. Formula: TP / (TP + FP)

Question 7

What is the Negative Predictive Value (NPV)?

Answer 7

% of negative tests that are true negatives. Formula: TN / (TN + FN)

Question 8

How does prevalence affect PPV?

Answer 8

Higher prevalence → higher PPV; lower prevalence → lower PPV

Question 9

Name 4 key WHO principles for effective screening

Answer 9

Recognizable early stage

Suitable, acceptable test

Early treatment is beneficial

Facilities for diagnosis and treatment must exist

Question 10

What must be balanced in any screening programme?

Answer 10

Physical/psychological harms vs. benefits and cost-effectiveness

Question 11

What are the 3 main UK cancer screening programmes?

Answer 11

Breast cancer: Double view mammogram

Cervical cancer: HPV + cytology

Bowel cancer: FIT test

Question 12

What is the FIT test?

Answer 12

Faecal Immunochemical Test – detects human haemoglobin with antibodies

Question 13

What are key advantages of FIT over gFOB?

Answer 13

One sample only

Detects only human blood

Higher sensitivity

Numerical/objective result

Increased uptake

Question 14

What happens with an abnormal FIT result?

Answer 14

Referral for colonoscopy within 2 weeks

Question 15

What % of colonoscopies in screening detect cancer?

Answer 15

10%

Question 16

Why was the bowel scope screening (flexisig) discontinued?

Answer 16

Superseded by better uptake/sensitivity of FIT

Question 17

Why is PSA test controversial?

Answer 17

It is organ-specific, not cancer-specific. Low sensitivity and specificity.

Question 18

What benign conditions can elevate PSA?

Answer 18

BPH, prostatitis, recent ejaculation, cycling, medications.

Question 19

What % of men with prostate cancer have PSA > 4.0 ng/ml?

Answer 19

80%

Question 20

What % of men with PSA ≤ 4.0 ng/ml still have prostate cancer?

Answer 20

0–40%

Question 21

Name 3 advanced PSA-based screening tools in research

Answer 21

Percent-free PSA

Prostate Health Index (PHI)

4Kscore test

Question 22

What is the UCL-led PRECISION trial about?

Answer 22

Recommends MRI before biopsy to reduce overdiagnosis and detect aggressive cancers

Question 23

Name 3 genes associated with high-risk prostate cancer

Answer 23

BRCA1/2, HOXB13, CHEK2

Question 24

What is the PCA3 gene?

Answer 24

Highly expressed in prostate cancer cells – detected via urine test

Question 25

Who is eligible for targeted lung screening in the UK?

Answer 25

People aged 55–74 who currently or previously smoked

Question 26

What test is used for lung cancer screening?

Answer 26

Low-dose CT scan

Question 27

What was the mortality reduction in women from lung screening?

Answer 27

~40–60%

Question 28

List 3 downsides of cancer screening

Answer 28

Psychological impact False positives/negatives Financial and access barriers

Question 29

Which of the following improves PPV the most in a screening test? A. Decrease test cost B. Increase test uptake C. Increase disease prevalence D. Increase specificity

Answer 29

C

Question 30

What makes the FIT test more acceptable to patients than the gFOB test? A. Lower cost B. Detects any blood source C. Needs only one sample D. Requires no referral

Answer 30

C