Breast cancer screening cannot be justified, says researcher
Book argues harm outweighs small number of lives saved, and accuses mammography supporters of misconduct
Sarah Boseley, health editor
The Guardian, Monday 23 January 2012
Women in the UK are called for breast screening every three years from the age
of 50.
Breast cancer screening can no longer be justified, because the harm to many
women from needless diagnosis and damaging treatment outweighs the small
number of lives saved, according to a book that accuses many in the scientific
establishment of misconduct in their efforts to bury the evidence of critics and
keep mammography alive.
Peter Gøtzsche, director of the independent Nordic Cochrane Collaboration, has
spent more than 10 years investigating and analysing data from the trials of
breast screening that were run, mostly in Sweden, before countries such as the
UK introduced their national programmes.
Mammography screening: truth, lies and controversy, from Radcliffe Publishing,
spells out the findings of the Nordic Cochrane group for laywomen, rather than
for scientists.
The data, Gøtzsche has maintained for more than a decade, does not support
mass screening as a preventive measure. Screening does not cut breast cancer
deaths by 30%, it saves probably one life for every 2,000 women who go for a
mammogram. But it harms 10 others. Cancerous cells that will go away again or
never progress to disease in the woman's lifetime are excised with surgery and
sometimes (six times in 10) she will lose a breast. Treatment with radiotherapy
and drugs, as well as the surgery itself, all have a heavy mental and physical
cost.
"I believe the time has come to realise that breast cancer screening programmes
can no longer be justified," Gøtzsche said. "I recommend women to do nothing
apart from attending a doctor if they notice anything themselves."
The book is published as a UK review of the evidence for breast cancer
screening, triggered by the Nordic Cochrane group's publications in scientific
journals, gets under way. In October, the cancer tsar Sir Mike Richards promised
an independent investigation of the data. It will be chaired by Sir Michael Marmot
and will include some eminent statisticians, none of whom have been involved in
the breast screening controversy before.
Richards has promised to act on its findings. "Should the independent review
conclude that the balance of harms outweighs the benefits of breast screening, I
will have no hesitation in referring the findings to the UK national screening
committee and then ministers," he wrote at the time.
Women in the UK are called for breast screening every three years from the age
of 50, and the age range is being extended to encompass all from 47 to 73. The
NHS screening programme has consistently disputed the Nordic Cochrane
Collaboration's work.
In July last year, in response to a paper that showed no difference in death rates
between similar pairs of countries that had introduced or not introduced
screening, Professor Julietta Patnick, director of the NHS cancer screening
programmes, said: "We can't comment on screening programmes in other
countries but here in England we do know that the best evidence available shows
that women aged 50-69 who are regularly screened are less likely to die from
breast cancer." She cited an estimate from the International Agency for Research
on Cancer (IARC) of the World Health Organisation which said mortality was
reduced by 35% through screening — a figure Gøtzsche disputes in his book.
Gøtzsche's book tells of personal attacks on him and on other researchers by the
pro-screening lobby, some of whom had financial interests in the continuation of
screening programmes, he alleges.
He compares screening advocates to religious believers and argues that their
hostile attitudes are harmful to scientific progress. A lot of false evidence has
been put forward to claim that the screening effect was large, he writes. Those
who tried to expose the errors came under personal attack, as if they were
blasphemers.
"I cannot help wonder why many people shrug their shoulders when they learn of
scientific misconduct and why many scientists don't care that they deceive their
readers repeatedly and betray the confidence society has bestowed on them,
whether for a political gain, for fame, for money, for getting research funding or
for any other reason. People may keep on being dishonest, may get away with it
and may publish in the same journals time and again, to the hurrahs of like minded
people who are often editors of the same journals," he writes.
Some of the screening trials were biased or badly done, the book says, for
instance by deciding on the cause of death of a woman after researchers knew
whether she had been screened for breast cancer or not. The best trials, it says,
failed to prove that lives were saved by screening.
Gøtzsche's group also found that one in three cancers detected by screening
was misdiagnosed.
Breast cancer deaths have gone down, he says, but better treatment and better aware
women, who go to the doctor as soon as they find a lump, are responsible.
Half of all breast cancers are found between screenings, he says.
Gøtzsche and his group have been highly critical of the leaflet sent to women by
the NHS screening programme, which, they say, inflates the benefits and
discounts the harms. He says he is hopeful that something good will come of the
review.
Klim McPherson, professor of public health epidemiology at Oxford University,
has been a critic of the information given to women by the NHS and is also
hopeful. He gives credit to Gøtzsche for his assiduous work over many years to
get to the truth. "His Cochrane reviews of breast cancer screening are of
extremely high quality and not to be lightly dismissed," he said.
Gøtzsche says his work is focused on helping women understand the risks and
benefits of screening. In the book, he says one of the leaders of the Swedish
trials claimed mammography was the best thing that had happened for women
during the last 3,000 years and added: "There are still people who don't like
mammography. Presumably they don't like women."
Gøtzsche sees it differently. "People who like women, and women themselves,
should no longer accept the pervasive misinformation they have consistently
been exposed to," he writes. "The collective denial and misrepresentation of facts
about over diagnosis and the little benefit there is of screening, if any, coupled
with the disregard of the principles for informed consent and national laws, may
be the biggest ethical scandal ever in health care.
"Hundreds of millions of women have been seduced into attending screening
without knowing it could harm them. This violation of their human rights is the
main reason we have done so much research on mammography screening and
also why I have written this book."
http://www.guardian.co.uk/science/2012/jan/23/breast-cancer-screening-notjustified