Professor Peter Gotzsche says women are being deliberately misled about the value of mammography screening.
Critics rubbish him. But is he that rare breed — an evidence-based conspiracy theorist?
In a stout brick community centre in a back street on Sydney’s north shore, Professor Peter Gotzsche is asking an audience why women have not taken to the barricades to express outrage at a major health scandal still largely unknown to the wider world.
“Women have been patronised and treated like children who cannot make their own decision,” he declares.
“They have been coerced into this, based on misleading information that has overstated the benefits and understated the harms, or omitted them altogether.”
The audience of about 80 men and women stares up at him enthralled as he goes on to condemn breast cancer screening programs — which, after 20 years, are generally seen as one of public health’s significant success stories.
You could dismiss Professor Gotzsche as just another conspiracy theorist — like the anti-vaxers or the fluoride obsessives — preaching to a gullible public their messages of mass harm at the hands of a health industry riddled with ugly self-interest.
But Professor Gotzsche is different. He’s a physician and co-founder of the Cochrane Collaboration, whose utterances are based solely on evidence that exists to back them up. Professor Gotzsche says he has come armed with facts, as well as words.
Working the numbers
Of course, that there is controversy over the overall risk vs benefit of breast cancer screening is not in dispute. Researchers crunch the numbers from the same clinical trials but have the ability to generate wildly different interpretations.
While they tend to agree that screening leads to harm from overdiagnosis, the divergence centres on how often this occurs.
A 2012 landmark UK review estimates somewhere between 11% and 19% of women who undertake mammographic screening are overdiagnosed.1
Professor Gotzsche, who said breast screening programs were unjustified back in 2001, tells you it’s 50%.
The director of the Copenhagen-based Nordic Cochrane Centre hit Australian shores last month to deliver a series of lectures on the topics of mammography screening, Big Pharma and the (allegedly) criminal way they have peddled useless but harmful psychiatric drugs.
The mammography talk is being held on a Friday night in the Sydney suburb of Chatswood.
The sky threatens rain.
The female MC — from the local Cancer Information and Support Society — introduces the Danish professor as “one of the bravest people I have heard of”.
“It takes a huge amount of bravery to be able to defend a profession that has been spawned by unethical companies, and medicine has certainly been taken over well and truly,” she says.
“I think we have a hero with us tonight.”
Professor Gotzsche, seemingly unfazed by this glowing reception, proceeds directly to a 30-minute PowerPoint presentation to canvas the scientific literature that supports his case.
As he clicks through a series of slides and graphs, Professor Gotzsche doesn’t mince words.
“You don’t live longer if you attend breast screening. That is my main message for tonight.”
His evidence includes his own 2013 Cochrane review of seven randomised clinical trials involving 600,000 women examining the effect of mammography screening on mortality and morbidity.2
The review concludes that while screening may reduce breast cancer mortality by 15%, it also leads to a 30% rate of overdiagnosis and overtreatment. It seems in the past two years, he has revised this overdiagnosis figure to 50%.
“A few years ago, I’d just had enough because very many scientists published deliberately dishonest science in order to tell the world there is virtually no overdiagnosis and screening has a huge effect,” he tells the audience.
“So I just needed to write the book [Mammography Screening: Truth, Lies and Controversy] pointing out how they torture the data until they confess.”
He goes on to tell the audience how screening kills at least as many women through overdiagnosis and subsequent overtreatment of harmless cancers as it saves.
“You could say it causes cancer, but don’t get me wrong. It is not the little radiation you get on a mammogram. It is because you find a lot [of cancer] you shouldn’t have found.”
This identification of indolent cancers leads to unnecessary radiotherapy that can cause potentially fatal complications such as lung cancer and heart disease, he tells them.
Screening also causes other harms, such as psychological distress, with false-positive results that occur after 10 mammograms for between 20% and 60% of women, he says.
He further claims that while the rationale for screening is to catch cancers early before they spread, evidence from Australia, Italy, Norway, Switzerland, the Netherlands, the UK and the US shows screening does not reduce the rate of advanced cancers.
In Norway, the risk of stage 3 and 4 cancer was exactly the same in the screened and non-screened populations.
Put simply, screening “can’t work”.
“The best prevention of breast cancer we have is telling women to stay at home and not go to screening,” he tells the audience.
These are the blunt conclusions based on his assessment of the evidence. However, it is his willingness to speak of malign intent behind the promotion of breast screening that takes him beyond the sober, much-qualified conclusions of the average Cochrane review.
Cancer societies and health agencies deliberately mislead women by highlighting the benefits of screening and downplaying the risks, he says.
“This is a public health scandal in my opinion.”
Talking of women who have been “patronised and treated like children”, of those women who have been “coerced” into screening based on misleading information, it is at this point he asks: “Why haven’t I seen women on the barricades?”
Competing voices
Professor Gotzsche is not the only medical researcher or world-renowned doctor who has called for national mammography programs to end.
Leading UK breast surgeon Professor Michael Baum — who established the first breast screening centre in south-east England in 1987 — resigned a decade later from the country’s national screening committee over the issue of informed consent. He later called for the UK’s screening program to be scrapped, arguing it was not effective in saving lives.
By 2012, in an editorial in the British Journal of Hospital Medicine, he conceded it was “politically unacceptable” and called instead for a risk-adjusted approach.3
Professor Alexandra Barratt, an Australian expert from the University of Sydney’s School of Public Health, says with so much controversy surrounding the topic, it is also vital the country has a robust debate and that women are given enough information about the risks and benefits to make up their own minds.
“Trying to work out what is the best evidence is difficult [partly because] those randomised trials are so old now,” she says.
“We have much better detection and treatment so mortality is going down. Trying to work out how much drop is due to screening, awareness and improved treatment is actually very difficult.”
But that debate is just not happening, Professor Barratt says.
Unsurprisingly, this claim is rejected by Breastscreen Australia. A spokeswoman told Australian Doctor that there were online resources providing information on the risks as well as the benefits of breast screening.
“The program has been successful in reducing mortality from breast cancer at the current participation rate of 56% in the target age group of women aged 50 to 69 years, by approximately 21% to 28%,” she says.
“Decreased participation will result in less cancers being detected.”
Cancer Council Australia’s public health committee chair Adjunct Associate Professor Craig Sinclair quotes the same stats in dismissing claims organisations like his use fear tactics to boost participation.
“There is no scaremongering in the promotion of mammography screening,” he says.
But he acknowledges screening has been the subject of debate for many years.
“The key dilemma is trying to determine a mortality benefit in some women against the occurrence of overdiagnosis in others, without ever being clear about who is likely to fall into which category,” Professor Sinclair says.
“In general, we take the same position as health authorities in the UK. The 2012 Independent UK Panel on Breast Cancer Screening estimated that, for 10,000 women invited to screen from age 50 over 20 years, 681 cancers would be diagnosed, of which 129 will represent overdiagnosis and 43 deaths from breast cancer will be prevented.
“On balance, we think this is a mortality benefit worth achieving and that mammography should be promoted accordingly as long as women are informed about the risks of overdiagnosis.”
Changing old habits
Back in Chatswood, Professor Gotzsche is fielding questions from the audience.
“So if the evidence is so clear, what do you think drives governments to continue screening?” one man asks.
The audience erupts into laughter.
The professor is deadpan.
“It’s incredibly difficult to stop a national program. There are so many faces to be saved, so many investments, such a large income and so much propaganda,” he says.
“Which politician would be ready to stand up after 30 years of one-sided propaganda and say, ‘Sorry folks, we were all wrong, but please vote for me next time.'”
A woman asked whether women should continue with other forms of screening?
“Well you ask me, so shall I give you an honest answer?”
“Please,” she replies.
“Bobby McFerrin — Don’t Worry be Happy,” he quips, referring to the 1988 hit song.
The crowd laughs once more.
“We have done the Cochrane review on monthly breast cancer self-examination,” he continues. “It doesn’t work. It only doubles the number of biopsies and therefore also the number of worries.
“Thermography was never shown to be effective, ultrasound was never shown to be effective, and considering how harmful mammography screening is … So join our males, we are happy, no PSA testing.”
Some cold hard facts
Could all his talk about deliberately misleading study conclusions, dodgy number crunching and vested industry interests leave him open to being labelled a conspiracy theorist — or, at the very least, a crusader with his own barrow to push?
And if so, does this damage the Cochrane brand?
Not according to Australian Cochrane Collaboration reviewer Professor Chris Del Mar, professor of public health at Bond University, Queensland.
“What Gotzsche has brought to the debate is hard cold facts. The evidence of benefit is more questionable than we thought initially, the harms more serious than we had assumed,” Professor Del Mar says.
“This has to be a good thing in any controversy.”
“We now think much more about the harms as well as the benefits, about the quality of the evidence and also the potential for conflicts of interest.”
“This has resulted in calls for potential patients to be much more carefully informed about what are the benefits and harms of screening.”
After Professor Gotzsche finishes his presentation, he speaks to Australian Doctor.
“There are very few people who know so much about breast screening as I do,” he says.
“I’m regarded as one of the leading experts in the world by leading observers such as BMJ editor-in-chief Fiona Godlee, so I know very well about this literature, and I had to write a whole book to expose some of the most important scientific misconduct in this area.
“So there isn’t any piece of good evidence that I don’t know about and don’t take into account, it just didn’t exist.”
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