How celebrities like Stephen Fry advocating prostate cancer testing could do more harm than good
It shows how our media’s obsession with eye-catching personal testimony, rather than empirical data, leads us astray. It’s also an example of the foolishness of looking to uninformed celebrities for health advice
“The Turnbull and Fry effect” sounds like something you might find in the footnotes of a Wikipedia page on quantum physics or cell biology.
In fact, it turns out to be something to do with celebrities talking about their harrowing experience of prostate cancer and encouraging other men to get tested for it by their doctors.
Since Stephen Fry and the former BBC Breakfast TV presenter Bill Turnbull revealed their diagnoses earlier this year there’s apparently been a surge in clicks on the NHS’s prostate cancer information pages and an almost 40 per cent annual increase in treatment.
Many men have seemingly acted on this advice. And the NHS is pleased.
“The Turnbull and Fry effect could help save lives,” enthused the NHS England chief executive Simon Stevens last week.
Yes it could. But, as we shall see, far fewer lives than most people think, or would be led to believe by the advocacy of Fry, Turnbull and Stevens.
And, more important, a surge of testing is very likely also to cause a great deal of pain and unnecessary discomfort to many more men.
The standard test for prostate cancer is the “prostate-specific antigen” (PSA) blood test. But it’s not a failsafe test. The PSA throws out a high percentage of false alarms.
Worse, a positive PSA result does not tell the doctor the precise location of a cancer. This can lead to multiple needle biopsies in search of a tumour which may, or may not, be there. These biopsies can leave men incontinent and impotent. And some die shortly after the full-blown prostate removal surgery that can follow.
There’s another serious deficiency of the PSA test. Most prostate tumours are extremely slow growing and will not kill the patient. Autopsies indicate that around four out of five men who survive into their eighties will have prostate cancer but not notice it or die from it. The PSA, and indeed a biopsy, cannot distinguish between the benign and the dangerously aggressive types. Many men could get invasive and damaging treatment that they simply did not need.
Let’s consider some outcome numbers. A comprehensive analysis of treatment studies by the Harding Centre for Risk Literacy found the following.
Of a sample of 1,000 men aged over 50 without prostate cancer screening, around seven will generally die from prostate cancer and 210 will die from any cause.
Of a sample of 1,000 equivalent men with screening around seven will generally die from prostate cancer and 210 will die from any cause. That’s correct: no statistical difference at all.
However, of those 1,000 men with screening around 160 would have a false alarm and a painful biopsy and 20 would generally have a benign, non-progressive, cancer and yet undergo unnecessary surgery.
As Gerd Gigerenzer, a German academic and who has been highlighting this problem for years, says in his book Risk Savvy: “Prostate cancer screening has no proven mortality reduction, only proven harm.”
It’s not impossible that early screening might be beneficial in a small number of cases. It may have helped Fry and Turnbull. But the data is clear that, on average, it will not help and mass screening for “men of a certain age” will do more harm than good – at least until medical science develops a far superior test to the crude PSA.
Prostate cancer is an example of how our media’s obsession with eye-catching personal testimony, rather than empirical data, leads us badly astray, especially when it comes to medicine; it’s also an example of the foolishness of looking to uninformed celebrities for health advice.
The health authorities should, of course, be trying to combat this tendency, not reinforcing it, as Stevens has done. Responsible physicians should be stressing the potential harm of testing and treatment, not simply gushing about the (exaggerated) benefits.
The £10m of investment Stevens promised last week to ensure men are “tested and treated” quickly would arguably be much better spent on anti-cancer public health prevention initiatives, such as advice on diet and lifestyle.
We have a particular problem in the UK. A Europe-wide survey conducted by Gigerenzer and his colleagues a decade ago found that 99 per cent of British men overestimated the benefits of PSA screening, turning in a worse performance than every other country studied.
A fifth of British men mistakenly believed that 200 out of 1,000 men would be saved by screening, rather than, the reality of virtually none. With this year’s “Turnbull and Fry effect” who would bet that the situation has improved?
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