Posted by: Margaret McCartney7 September 2012
Here's the thing – I was thinking that the political intrigue, skullduggery and deception in Denmark, as seen by Sarah Lund in The Killing and Danish politicians in Borgen, was fictitious.
Surely Scandinavia is a civilised land, standing up for women's rights and decent liberal causes, giving the world Volvos and Ikea?
Not a bit of it. Reading Professor Peter Gøtzsche's new book 'Mammography screening: truth, lies and controversy 'dispels any such rosy misconceptions. He is the lead for the Nordic Cochrane Centre based in Copenhagen, and has consistently published on breast screening over the last decade. I've been following the research and debate and thought I had a decent understanding of the story.
To my surprise, I didn't. Sure, it was easy to see there were professional arguments over screening that reverberated around most of Europe, and sometimes Stateside too – but I didn't expect the degree of acrimony, personal attack and straightforward bad statistics Professor Gøtzsche describes.
His book is painful reading to those of us who would like to believe contemporary research is all about the science.
It is his conclusion that breast screening probably doesn't work, that the benefits – if any – are marginal and the harms great.
He demonstrates that the evidence on which breast screening programmes were set up was inadequate.
He also describes the hostility he and his team have been subjected to during their decade-long research in the area.
Risks and benefits
Why is this? Why can't debate be about the science?
When there is emotional investment, it becomes harder to disentangle risks and benefits clearly. We have become societally attached to screening, despite the evidence demonstrating how marginal the benefits and how frequent the harms.
We are usually, as a profession, better at doing this when it comes to alternative medicine – it's far less acceptable for GPs to mete out homeopathy or acupuncture just because they believe it works.
We have learned to counter anecdote by citing randomised trials, and a degree of humility when we remember the enthusiasm for other non-evidenced and equally dubious interventions, like frontal lobotomy and routine hysterectomies.
Yet with screening, the lure of ‘catching it early' and the emotive hard sell seems to circumvent our usual hard look at the evidence.
In many ways, many of the screening tests we offer owe their evidence to the ‘doctor knows best' school of medicine that has otherwise been rightly banished.
In Professor Gøtzsche's book, a reprint of one particularly odious US advertisement reminds us of just how bad it can get: an advert saying that if you don't go for your routine mammogram you need ‘more than your head examined'.
A few years ago Professor Mike Baum, a breast surgeon involved in setting up the breast screening programme in the UK, wrote Breast beating, in which he described the personal cost of opposing the unrelenting push for more screening.
Last year an independent review of breast screening in the UK was announced. There are two problems it has to consider: firstly, if it is worthwhile to continue at all, and secondly, if women should be, as they currently are, encouraged to have breast screening or – more simply and more ethically – to consider whether they would like it.
I suspect that if more women read Professor Gøtzsche's book, they would answer with a decrease in footfall to the screening programme.
This review is a big chance for screening to catch up with science, to ditch the personal attacks and start concentrating on improving public health instead. I predict that in a few decades, we will look back on breast screening with the same raised eyebrows we currently reserve for Reiki.
Dr Margaret McCartney is a GP in Glasgow