Controversy Erupts Around Breast Cancer Screening Leaflet in the UK

Zosia Chustecka

February 26, 2009

February 26, 2009 — In the United Kingdom, a leaflet about breast cancer screening sent to women along with an invitation for a mammogram will be rewritten after fierce criticism from experts, who described it as inadequate and manipulative.

At the center of the controversy is the question of whether or not the leaflet fairly and accurately describes the balance of risks and harms involved with screening mammography.

The leaflet, Breast Screening: The Facts, was produced by the UK Department of Health. It was originally written in 2002, and was updated in 2006.

It will now be scrapped and rewritten, according to news reports.

Prof. Mike Richards, National Cancer Director, said a formal review is now in progress, and the new leaflet will likely be ready by Fall 2009.

The announcement was made this week, only days after severe criticism of the leaflet appeared online January 27 in BMJ and was highlighted February 19 in a letter to The Times newspaper. The letter was signed by 23 cancer experts, epidemiologists, family doctors, and patient representatives.

"None of the invitations for screening comes close to telling the truth," says Michael Baum, MD, emeritus professor of surgery at University College, London, United Kingdom, who headed the list of signatories to The Times letter.

None of the invitations for screening comes close to telling the truth.

"As a result, women are being manipulated, albeit unintentionally, into attending," they write. It is "imperative" that this leaflet is rewritten.

Not Telling the Truth?

The UK breast screening program, started in 1990, invites all women between 50 and 70 years to undergo a mammogram, for free, every 3 years. The leaflet that has come under such criticism was sent out with this invitation, and sets out to explain what to expect from the screening.

The leaflet is "inadequate as a basis for informed consent," say Peter Gøtzsche and colleagues at the Nordic Cochrane Center, in Copenhagen, Denmark, writing in BMJ. It emphasizes the benefits of screening — inaccurately, in their opinion — but gives little information about harms, they write.

In particular, it makes no mention of the major harm of screening — that is, unnecessary treatment of harmless lesions that would not have been identified without screening, Dr. Gøtzsche and colleagues point out.

"This harm is well known and acknowledged, even among screening enthusiasts," they add. "It is in violation of guidelines and laws for informed consent not to mention this common harm, especially when screening is aimed at healthy people."

The leaflet does note that some women find mammograms to be painful and uncomfortable, and that recalls for further investigations "can cause worry." However, it does not elaborate on the fact that some of these recalls result in false-positive diagnoses, and makes no mention at all of the diagnosis of ductal carcinoma in situ (DCIS), which accounts for about 20% of the diagnoses made in the UK breast screening program. Fewer than half of these DCIS cases progress to invasive cancer, they note.

Dr. Gøtzsche and colleagues also take issue with how the benefits of screening are described. The leaflet proclaims that screening "reduces the risk of the women who attend dying from breast cancer" and estimates that it saves about 1400 lives in the United Kingdom each year.

But "it has not been proven that screening saves lives," they insist, and new evidence shows less benefit and substantially more harm from screening than previously thought.

In fact, this balance between risk and benefit has changed so much in recent years that nationwide programs of breast screening would be unacceptable, they say. "We believe that if policy makers had had the knowledge we now have when they decided to introduce screening about 20 years ago . . . we probably would not have had mammography screening."

Conflict of Interest?

A major problem with this information on breast screening is that it comes from the same organization that runs the screening program, and this represents a conflict of interest, say Dr. Gøtzsche and colleagues. Information about harms may deter women from participating, and high participation rates are pivotal for these programs to be successful.

The UK breast screening program is considered a success — during 2007/08, of the 2.2 million women invited for checks, 1.7 million were screened, The Times reports.

The Nordic Cochrane researchers have written on this issue previously, and have also criticized leaflets on breast cancer screening in 6 other countries that have publicly funded screening programs — Australia, Canada, Denmark, New Zealand, Norway, and Sweden (BMJ. 2006;332;538-541).

At that time, and now again, Dr. Gøtzsche and colleagues offer a template document that provides evidence-based information on breast cancer screening; it can be downloaded from The Nordic Cochrane Centre website.

In this document, they set out the benefits and harms, as follows:

  • If 2000 women are screened regularly for 10 years, 1 woman will benefit from screening; she will not die from breast cancer.

  • At the same time, 10 healthy women will become breast cancer patients and will be treated unnecessarily, many undergoing surgery, radiotherapy, and chemotherapy.

  • About 200 healthy women will experience a false alarm.

 

"The question of whether the benefits of screening outweigh the harms is a value judgement that needs to be made by invited women," Dr. Gøtzsche and colleagues conclude. In order to make that decision, the woman needs to be informed — and they hope that their leaflet provides sufficient information to enable women, together with their doctors, to decide whether to participate.

But Numbers Are Disputed

In their letter, Dr. Baum and colleagues urge the British authorities use this template to rewrite the current leaflet. It gives a clear overall picture of how the benefits and harms stack up, they say, although they admit that there is some debate about the exact numbers; some data suggest that more women benefit and fewer are treated unnecessarily.

These numbers are disputed by government-appointed experts. Julietta Patrick, director of the National Health Service (NHS) Cancer Screening Programmes, says the estimated numbers are nearer to 4 to 5 lives saved and 4 to 5 women being unnecessarily treated, so the ratio is closer to 1:1. Her comments appear in an article about the recent reports on the NHS website, and these same figures were used by the head of cancer policy, Prof. Richards, when talking to the press.

"There are no doubts in my mind about the benefits," Prof. Richards said.

There are no doubts in my mind about the benefits.

Although the presentation of information can be debated, it is "dangerous to scare people away from a program that has bought substantial benefits," said Peter Johnson, MD, chief clinician at Cancer Research UK.

The NHS website article points out that the Nordic Cochrane group previously published a systematic analysis, which concluded that "screening likely reduces breast cancer mortality," with about a 15% relative risk reduction.

It also explains that most of the harms associated with screening relate to the uncertainty about DCIS. Although only about half of these cases go on to develop invasive cancer, it is not possible to predict which ones will, so all women with screen-detected DCIS are treated in the same way, with surgery/ radiotherapy or chemotherapy. For those women who would not have developed invasive cancer, this treatment would have been unnecessary.

Complete Rethink Needed?

Dr. Baum argues that there is no evidence of large benefits. "The number of invasive breast cancers being detected is not falling, despite the number of cases picked up by screening rising dramatically," he told The Times. "You would expect serious cancers to drop because the early detection means the DCIS cases are not progressing. It just doesn't add up."

The policy of screening every woman should be revised to focus on those most at risk, factoring in family history and demographic trends, he suggested. In addition, he questioned the current trend for aggressive treatment, and suggested that there may be room for a "watchful waiting" approach such as in prostate cancer.

"It is complacent and arrogant to think we should carry on regardless with screening services," Dr. Baum said. "It is time we had a complete rethink, but anyone who dares challenge the sacred cow of screening has a terrible time."

BMJ. Published online before print January 27, 2009.

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