Bob Bury

Now I’m a patient I realise the relative risk anxieties of investigation and treatment

In my previous life as a radiologist, I took a special interest (for reasons which currently escape me) in radiation hazards and the protection of patients and staff. This led to me becoming, almost by default, the Royal College of Radiologists’ spokesperson on the issue.

You might think that radiologists would all be keenly interested in radiation protection, but you’d be wrong, so having put my head above the parapet, I was clobbered for all sorts of meetings and committees on the topic. One of these was the Department of Health group responsible for the implementation of the Ionising Radiation (Medical Exposures) Regulations, 2000, or IRMER as the legislation came to be known, not always fondly.

The object of having regulations concerning the use of ionising radiation at all is to protect patients and staff from unnecessary exposure, and the underlying culture was one of getting people (especially clinicians) to take radiation seriously and avoid unnecessary examinations.

However, it became apparent to me over the years that there was another problem; namely that patients and clinicians sometimes took the risks of radiation much too seriously. So; it wasn’t unusual for obstetricians to refer their patient who had symptoms of pulmonary embolus for a lung scan, but hesitate to ask for the CXR, without which the scan couldn’t be interpreted, because they didn’t want to expose her to additional radiation.

It was good that they took the radiation seriously, but clearly (to me, at least, see below), the tiny risk from the radiation was greatly outweighed by that of missing a PE, or anticoagulating a pregnant patient unnecessarily.

Then there was the one and only time that I was asked to give my opinion in a legal case. The complainant was a chap who had been involved in a serious RTA; he developed shock lung and spent several days on a ventilator in the intensive care unit. Thanks to skilled medical and nursing care, he survived.

His first action on leaving hospital was to sue his carers. Why? – well, it had come to his attention that while he was unconscious on ITU, he had been subjected to a number of chest x-rays, and the radiation involved could put him at risk of developing cancer. Well, he was right of course – it could. But that risk is tiny, and those chest radiographs had been instrumental in the care which resulted in him surviving a condition with c. 50% mortality.

I gave my opinion, which was that the chap needed a good slap (although I dressed it up a bit) and the case went no further, but it does illustrate the lack of a sense of proportion which bedevils discussions around radiation and its possible adverse effects.

As a result of these, and other similar experiences, it had long been my opinion that we should spend less time teaching children trigonometry, which they’ll never use, and more on instructing them in probability theory and risk/benefit analysis. I just didn’t see why patients couldn’t understand that most treatments had a downside, and that it was simply a matter of assessing the relative risk of allowing their illness to go undiagnosed or untreated on the one hand, and that of investigating or treating them on the other.

If the disease was significantly more threatening than the treatment, then the decision was easy – I railed against those who insisted that all treatments should be 100% safe, and against the anti-vaccine lobby in particular.

Then I retired and promptly, as is the way with these things, developed my first ever significant illness. This required immunosuppressive treatment, involving the use of retuximab.

The nephrologist told me that, like most drugs, there was a list of side effects as long as your arm, which I could Google if I was feeling masochistic, but that the one he was required to draw to my attention was the risk of developing progressive multifocal leukoencephalopathy. This is a relentless and uniformly fatal form of brain-rot, and the size of the risk was between 1:5000 and 1:10000.

That was when I discovered that risk/benefit assessment is much easier when it’s someone else who is at risk. I mean, it was a non-brainer wasn’t it? Take the drug, with its relatively tiny risk, or allow my body to reject its own kidneys and be fairly sure of ending up on dialysis or worse. It should be an easy decision, but suddenly 1:5000 didn’t sound like such a good bet, not when certain death as a gibbering wreck was the result if my number came up.

I then began to realise that I might have been a bit harsh* in my assessment of the patients who worried ‘unnecessarily’ about the risks of investigation and treatment – the numbers seem more threatening when you are the one at risk.

Obviously, I did the sensible thing, and took my medicine like a man, but in the process discovered that intellectual acceptance of a small risk doesn’t mean that you don’t worry about it.

In the unlikely event that I should ever again be called upon to explain to a patient that the estimated 1:2000 risk of radiation-induced cancer from a whole body CT scan is negligible compared to the risk of not having the test, I hope I’d be even more understanding than I was in the past.

*But not about the anti-vaccine lobby – they really are either terminally stupid or evil.

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One Response to “Now I’m a patient I realise the relative risk anxieties of investigation and treatment”

  1. neilh says:

    Couldn’t agree more, recently went through mental turmoil over whether to have yellow fever vaccine for South America trip as odds of contracting yellow fever were about the same as the risk of serious vaccine-related complication in over 60’s!

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