The new NHS breast screening leaflet fails to impress

  • The best evidence that we have about the effectiveness and harms of breast screening comes from a large review done independent of the breast screening industry –  with a patient information booklet available  here – which states that
    • It may be reasonable to attend for breast cancer screening with mammography, but it may also be reasonable not to attend because screening has both benefits and harms
    • If 2000 women are screened regularly for 10 years, one will benefit from the screening, as she will avoid dying from breast cancer
    • At the same time, 10 healthy women will, as a consequence, become cancer patients and will be treated unnecessarily. These women will have either a part of their breast or the whole breast removed, and they will often receive radiotherapy and sometimes chemotherapy
    • Furthermore, about 200 healthy women will experience a false alarm. The psychological strain until one knows whether it was cancer, and even afterwards, can be severe

So. The new leaflet intended for women being given breast screening appointments had been hoped to address the disparity in information. The fact that there was to be an updated leaflet was was announced shortly after this letter had been published in the Times in 2009.

I don’t like the new leaflet. I have tried to see past the pink flowers on the front, which annoy me before I get to the text.

The benefits of breast cancer screening are listed as

-the earlier breast cancer is found the better your chance of surviving it

-if breast cancer is found early you are less likely to have a mastectomy or chemotherapy.

The downsides are listed – in order – as xray exposure, false negatives, false positives, the finding of non harmful ‘cancers’ and anxiety.

In some ways this is a slight improvement. Radiation wasn’t mentioned directly as a harm in the previous equivalent leaflet.

And it does mention DCIS (ductal carcinoma in situ) as a cause of a quarter of screening cancer diagnoses (although I think their wording could be clearer.) Critically, though, they say that they use ‘treatment’ for all DCIS but they don’t make clear that a minority of DCIS go on to invasive cancer, often over decades, and  what that treatment is – it is often mastectomy.

But the biggest problem is the numbers they give right at the end. They say that ‘for every 400 women screened regularly for 10 years, one less will die from breast cancer.’

This figure is troubling. It is not based on the best available data, and the source for these figures has never been made clear to me, but here’s the trail.

The original reference is here, in the Journal of Medical Screening from 2006 in a paper written by the Advisory Committee on Breast Cancer Screening:

“The International Agency for Research on Cancer (IARC) concluded that the 25% reduction in mortality seen in the trials of mammographic screening, based on an ‘intention to treat’ analysis, implies a reduction in breast cancer mortality of about 35% for women who are screened regularly. The effectiveness of screening in the NHSBSP is influenced by programme factors, such as the introduction of two views and the optimization of optical density, and also by population factors, such as the increasing use of hormone replacement therapy during the 1990s. The current NHSBSP saves an estimated 1400 lives each year in England.”

And that’s it. Note the word ‘estimated’.

As for the IARC, here’s the info from the WHO website, from 2002.

“The available evidence on breast cancer screening was evaluated in Lyon by a Working Group convened by the International Agency for Research on Cancer (IARC) of the World Health Organisation (WHO), from 5-12 March 2002. The group, consisting of 24 experts from 11 countries, concluded that trials have provided sufficient evidence for the efficacy of mammography screening of women between 50 and 69 years. The reduction in mortality from breast cancer among women who chose to participate in screening programmes was estimated to be about 35%.”
Yes, it’s ESTIMATED again.

Compare that to the work of the Nordic Cochrane Centre who actually got the studies and looked for the evidence: see here.

And at the end, there’s more of those pink flowers. I may yet weep.

9 Responses to “The new NHS breast screening leaflet fails to impress”

  1. Anna December 31, 2010 at 1:57 am #

    I have had my eyes opened within the last few months and certainly will not take up my next invitation for breast screening.

    Why, with all the evidence, is breast screening still being promoted as a defence action? Surely, in these mean times, the NHS would benefit financially in publishing a factual leaflet.

    Anna :o]

  2. Yvonne December 31, 2010 at 7:18 pm #

    Ive noticed my practice nurse to whom I have to report every six months to get my blood pressure taken – half a morning off work for something I could do myself – in order to get my HRT script,. has stopped trying to pressurise me into mammograms that I have steadfastly refused for several years. At one time she got quite insistent until I made myself perfectly clear. Could it be that a more balanced view of all this screening is getting through? also reminds me of the leaflet that was posted to me with an appointment for the colposcopy clinic – the leaflet said phone to discuss any questions – when I did I was told “That’s not our leaflet – it’s the SHA’s” I was speechless.

    As a punter I no longer trust health advice from the government, ever since pregnant women were told that there is no safe level of alcohol for them. Unless advice is based on the best available scientific advice it is entirely discredited in my view.

  3. Margaret McCartney
    margaretmccartney January 2, 2011 at 8:17 pm #

    You’re right Yvonne. It’s still not clear to women that as adults they have the right to a CHOICE about screening. It’s not something that should be pushed on anyone.

    As for a more balanced view, from the inside of the NHS, I don’t see it, sadly.

    I’m writing the chapter just now on breast screening and am recalling a conversation with Edwina Currie about it (she was health minister at the time it was set up and felt it was one of her ‘achievements’) . It was very clear to me that it was all about politics, and very little about women’s health. While it remains so, especially with NICE now emasculated, I’m not hopeful….

  4. health and well being January 10, 2011 at 9:19 pm #

    l was quite shocked when l discovered a lump in my breast that the doctor refused to give me a less invasive ultrasound and insisted on an invasive mammogram because 2 weeks earlier l turned 35 and 35 is the cut off for having a mammogram, can they ever throw their books away and look at the person. l declined and 3 months later my lump went away!

    camilla

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  8. BGam January 28, 2012 at 1:41 pm #

    Thank you for your blog. My first breast screen appt has come and is due in a few days (I will soon be 48)
    After doing research, I do not like the idea of CT one bit. I would prefer ultrasound, mri or themography. What do you think about the safety of these? I get what you about false positives and the danger of treating just in case though. If there is some family history then it is more tempting to get screened at some stage in your life.
    My Grandmother has a masectomy in her mid or late 70’s in the late 1980’s in Canada. She died about 90 years old, possibly from cancer in the end but it was not discussed. My older sister (a nurse at the time) later said she thought the masectomy need not have been done.
    If I ask my doctor about whether i have an increased risk, how do I know I am getting an honest answer?
    I am thinking that for now, it’s better not to go to the screening. But would like honest input from a doctor.

  9. Margaret McCartney
    margaretmccartney January 28, 2012 at 10:25 pm #

    hello
    the honest answer is that I don’t know. The NHS breast screening programme uses mammography, which is xrays, and not CT (which also uses xrays but can produce different types of image.)
    The work on MR as breast screening has mainly been done in women at higher genetic risk of breast cancer, hence is not immediately applicable to women at ordinary risk.
    I am sure that your doctor would be able to help put your personal risk factors and views on screening, plus your values, into some kind of order. It may be that the breast screening service director would also be able to help (they are usually radiologists)
    The Nordic breast cancer leaflet is here
    http://www.cochrane.dk/screening/mammography-leaflet.pdf

    Ideally we should have online and paper based decision aids in the same way that we have for PSA screening – the problem is that we don’t yet see breast screening as a choice to be made, with pros and cons attached.

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