Bob Bury

Playing The Odds

It's often said that we are not training enough scientists, but I'm much more concerned that our schools aren't teaching the non-scientific majority how to understand the impact of science, and especially medical science, on their lives.

Take radiation. We all know that it can be harmful, and people

like me, who spend their working lives irradiating patients, make

great efforts to keep the doses used to a minimum. But we need to

maintain a sense of proportion. There was a case recently of a man

who spent weeks on a ventilator in an intensive care unit after

a severe road traffic accident. His chances of survival were less

than evens, but, thanks to the skill of the nursing and medical

staff, he made a full recovery. His first action on going home?..he

sued the hospital. Why? Because he had become aware that while he

was unconscious, he had been subjected to a number of chest x-rays,

and he was concerned that the radiation might have damaged his health.

And it might have done, but the risk to health from a chest x-ray

is tiny, unmeasurable, and without regular x-rays to monitor the

condition of his lungs, he would almost certainly have died. It's

all about balancing risk and benefit.

And then there are the 'side effects' of medicines. I'll let you

in on a secret. There is no such thing as a side effect. Drugs are

chemicals that are likely to have several effects on our bodies,

only one of which will be the desired, therapeutic, one. A side

effect is just an unwanted effect, in the same way that a weed is

just a plant in the wrong place. Good medicine consists of choosing

the right drug in the right dose, and balancing the possibility

of these unwanted effects against the chance of cure.

All of which illustrates an uncomfortable fact that doctors seldom

talk about in front of patients in case they frighten them. Medicine

is a percentage game; we don't deal in certainty, in black and white,

but in shades of grey. We play the odds in an informed way, hopefully

ensuring that the investigation and treatment we prescribe has net

benefit for the patient. But it is possible to get everything right,

and still do harm to the patient. For the tabloids of course, every

adverse outcome in medicine is a 'blunder' or a 'scandal', and occasionally

they are right, but often it's just the laws of chance conspiring

against patient and doctor.

Rightly or wrongly, doctors haven't always been completely open

with patients about the risks of investigation and treatment, but

that's all changing. Consent to treatment can only be truly 'informed'

if patients are told of all the significant risks involved, and

if we want them to make sense of this new information without being

frightened witless, schools must devote less time to heating test

tubes over bunsen burners and more to exploring the concept of relative

risk. Our friends in the media could do with a refresher course,

too.

- June 2004

About the Author

Consultant Radiologist