Public health

Question 1

What is a screening

Answer 1

Application of test(s) to people who are apparently free from the disease in question in order to sort out those who probably have the disease from those who probably do not

Not intended to be diagnostic

Purpose is to interrupt natural history of a disease as its asymptomatic stage when it is treatable and progression can be halted

Question 2

10 principles of screening

Answer 2

Condition is an important health problem

Natural history is well understood

Recognisable in early stages

Treatment is better in early stages

Suitable test exists

Acceptable test exists

Adequate facilities exits to cope with abnormalities detected

Screening is done at repeated intervals when onset is insidious

Chance of harm is less than the chance of benefit

Cost is balance against benefit

Question 3

Advantages of cancer screening (7)

Answer 3

Reduced mortality

Reduced morbidity

Reduced incidence of invasive cancer

Improved prognosis for individual patients

Identification of high risk groups and opportunities for primary intervention

Reassurance for those screened negative

Cost savings

Question 4

Disadvantages of cancer screening (6)

Answer 4

Detection of cases already incurable may increase morbidity for some patients

Unnecessary treatment for lesions which may not have progressed

Psychological trayma for those with false positives

False reassurance for those with false negatives

Reinforcement of bad habits amongst those negative

Costs