Blue Book: Screening Principles

Question 1

Why screen for cancer?

Answer 1

The identification of early stage disease allows more effective, potentially curative treatment to be used. As early stage disease is frequently asymptomatic, screening may be used to identify tumours before clinical presentation.

Question 2

What characterisitcs of both screening and tumour should be satisfied?

Answer 2

Tumour:

• Be curable when detected early.
• Be relatively common
• Have a long pre-invasive or non-metastatic stage.
• Be able to be detected by relatively simple tests.
• Be distinct from benign lesions.

Test:

• Be able to detect cancer at an early enough stage ti implement effective treatment.
• Be sensitive: able to distinguish tumours clear and give low false negative value.
• Be specific: would not give false positives.
• Be well tolerated
• Be easy to administer/perform
• Be inexpensicve
• Be well publicised

Question 3

What are the advantages of screening?

Answer 3

• Reduction of mortality by detecting early disease that is curable.
• Less radical treatment hence reducing morbidity.
• Saving on health service resources by increased cure rates.
• Reassurance given by a negative test.

Question 4

What are the disadvanatges of screening?

Answer 4

• Increased length of anxiety and morbidity if no effective intervention is possible.
• The over-investigation of false positive cases with associated morbidity.
• Over-treatment of borderline cases that do not require treatment.
• False reassurance from a false negative result.
• Possible harmful effects of the screening test.
• Cost of screening a large population.

Question 5

What screening programmes are in place in the UK

Answer 5

Breast, Cervical and colorectal.

Question 6

Describe Cervical Screening

Answer 6

All women aged 25-64 offered screening every 3 years. After every 5.

Question 7

Breast Cancer

Answer 7

Regular mammography is offered to women aged 50-70 every 3 years. Screening of young patients who are at risk, eg FHx should be considered.

Question 8

Colorectal Cancer

Answer 8

Men and women offered faecal occult blood (FOB) every 2 years between the ages of 60-69.

At risk patients, eg UC, FHx or previous tumour should be screened with existing management plan