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 programs.
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 programs 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 program 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 programs, said: “We can’t comment on screening programs 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 likeminded 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 program, 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 overdiagnosis 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 healthcare.
“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.”