4 – Earlier is not necessarily better
In this Chapter:
- Introduction (this page)
- Lessons from neuroblastoma screening
- Weighing benefits and harms
- Phenylketonuria screening: clearly beneficial
- Abdominal aortic aneurysm screening: proceed with care
- Breast cancer screening: well established but remains contentious
- Prostate cancer screening: clear harms with uncertain benefits
- Lung cancer screening: early but not early enough?
- Genetic tests: sometimes useful, often dodgy
- What screening aims to achieve and why evidence matters
- Is anyone normal?
- References (Chapter 4)
- Earlier diagnosis does not necessarily lead to better outcomes; sometimes it makes matters worse
- Screening programmes should only be introduced on the basis of sound evidence about their effects
- Not introducing a screening programme can be the best choice
- People invited for screening need balanced information
- The benefits of screening are often oversold
- The harms of screening are often downplayed or ignored
- Good communication about the benefits, harms, and risks of screening is essential
In the previous sections we have shown how treatments that are inadequately tested can cause serious harm. Here we turn our attention to screening apparently well people for early signs of illness. Screening sounds so sensible – how better to ward off serious consequences of disease and stay healthy? While screening is helpful for several conditions, screening can harm as well as help.
From person to patient
Screening will inevitably turn some people who test ‘positive’ into patients – a transformation not to be undertaken lightly.
At best, screening should only be offered to the healthy people it seeks to reassure or treat if there is sound evidence that: (a) it will do more good than harm at an affordable cost; and (b) it will be delivered as part of a good quality and well-run programme.
Screening is much more than a ‘one-off’ test. People invited for screening need sufficient unbiased, relevant information so that they can decide whether to accept the offer or not – that is, they need to know what they are letting themselves in for.
One way of thinking about screening is like this: