Women kept in the dark about the facts about mammography

Mammography is a widely advocated and popular intervention designed to pick up breast cancers earlier than they would otherwise be, and therefore allow less invasive and more effective treatment. However, as I pointed out in a blog back in 2007, some researchers believe that the benefits of mammography are somewhat overblown, and that the potential downsides are at the same time downplayed or not mentioned at all. A major problem with mammography is that it may detect cancers that would not go on to trouble women during their lifespan. This can obviously subject women to unnecessary stress and anxiety, not to mention unnecessary treatment in the form of, say, surgery, radiotherapy and chemotherapy.

The debate about the relative benefits and harms of mammography has reared up again in the UK because of the publication of a letter in the Times newpaper which can you read here. In it, 23 interested parties cite evidence that is published by the researcher Peter Gøtzsche and his colleagues from the independent Nordic Cochrane Centre in 2006 [1]. This review of the available literature concluded that: for every 2000 women invited for screening throughout 10 years, one will have her life prolonged. In addition, 10 healthy women, who would not have been diagnosed if there had not been screening, will be diagnosed as breast cancer patients and will be treated unnecessarily. It is thus not clear whether screening does more good than harm.

The letter in the Times appears timed to coincide with the print publication of an article by Peter Gøtzsche and colleagues in this week’s British Medical Journal [2]. The article outlines some of the apparent deficiencies and omissions in the information given to UK women regarding breast screening. The article refers to the UK Department of Health (DoH) leaflet entitled ‘Breast Screening; the Facts’. The authors of the article make the point that the title of the leaflet suggests the information can be trusted. But can it?

The authors of the BMJ piece make the point that the DoH leaves no doubt that screening is good for women, and quote excerpts from the leaflet which include: “Why do I need breast screening?”, “If changes are found at an early stage, there is a good chance of a successful recovery,”. The leaflet also claims that breast screen saves “an estimated 1400 lives each year in this country” and “reduces the risk of the women who attend dying from breast cancer.”

However, according to the authors, the leaflet has many deficiencies which mean that women cannot make informed decisions about whether they attend breast screening or not.

For instance, no mention is made of the major harm of screening”that is, unnecessary treatment of harmless lesions that would not have been identified without screening. 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 new guidelines from the General Medical Council state: “You must tell patients if an investigation or treatment might result in a serious adverse outcome, even if the likelihood is very small.” The likelihood of being overdiagnosed after mammography is not very small; it is ten times larger than the likehood [sic] of avoiding death from breast cancer.

The leaflet notes that about one in every 20 women screened will be recalled for more tests because of ‘false positive’ results (results that suggest a problem when, in reality, there is none). But, as Gøtzsche and colleagues point out, the more screenings a woman has, the more likely she is to end up with a false positive result. They cite evidence that shows that after 10 screens, risk of false positive diagnosis was 50 per cent in one piece of research and 20 per cent in another. The authors add: We now know that the psychosocial strain of a false alarm can be severe and may continue after women are declared free from cancer.

Basically, mammography can lead to women have unnecessary treatment including radiotherapy. Gøtzsche and colleagues point this out, and also explore some of the risks associated with this. They note that the leaflet tells women that the dose of radiation from mammography is very small, but does not tell women of the risks associated with healthy women having radiotherapy. They cite evidence that radiotherapy suggesting that radiotherapy may double the risk of death from heart disease and lung cancer. The authors that that Technological improvements may have diminished these harms to some extent, but they are still important.

The authors also tell us that the leaflet summary implies that screening leads to fewer mastectomies. In fact, research shows that screening leads to 20 per cent more mastectomies being performed.

Also, we are told that the leaflet expresses no reservations about screening older women, only a scare that the breast cancer risk increases with age, although it has not been shown that screening these women decreases their risk of dying from breast cancer. Furthermore, the problem with overdiagnosis becomes more pronounced, and the likehood of gaining any benefit smaller, due to competing risks of death.

And, finally, the authors point out that it has not been proven that screening saves lives. While it may reduce the risk of breast cancer mortality (by about 15 per cent), studies show that breast screening does not decrease total cancer mortality. As the authors point out This indicates that the benefit of screening is likely to be smaller than generally perceived.

The authors then conclude: We believe that if policy makers had had the knowledge we now have when they decided to introduce screening about 20 years ago, when nobody had published data on overdiagnosis or on the imbalance between numbers of prevented deaths from breast cancer and numbers of false positive screening results and the psychosocial consequences of the false alarms, we probably would not have had mammography screening.

This is one group of reseachers’ view, and not everyone will share it. The figures regarding those that benefit and those who may come to harm have been disputed. However, there can be little doubt that many women are simply not being informed of the full facts about breast screening. So one figure I think we can be certain of is that chances of these women making a truly informed decision about mammography is zero. I’m not against mammography, but I am against women being kept in the dark about the true benefits and risks associated with this practice.


1. Gøtzsche PC, Nielsen M. Screening for breast cancer with mammography. Cochrane Database of Systematic Reviews 2006, Issue 4. Art. No.: CD001877. DOI: 10.1002/14651858.CD001877.pub2.

2. Gøtzsche PC, et al. Breast screening: the facts”or maybe not. BMJ 2009;338:b86

21 Responses to Women kept in the dark about the facts about mammography

  1. Anne 20 February 2009 at 9:20 pm #

    After my last routine mammography I was recalled because they noticed something. The recall was a week later but it was one of the worst weeks of my life thinking I must have breast cancer. The ‘something’ they saw turned out to be simply overlapping breast tissue, so radiographer error in a sense. I’m not sure I will ever have a mammogram again.

    Neither will I have a smear test – after having them since my early twenties every three years I’ve had enough ! I don’t know if that’s sensible but I understand there is controversy about smear tests too.


  2. Angie 20 February 2009 at 11:08 pm #

    I have always maintained this, and would never dream of subjecting myself to testing involving radiation (to avoid cancer?? huh?), especially if I had no intention of pursuing the treatment ‘options’ offered.

    The same sort of thing applies as regards testing to cervical smear tests – pace what is happening to Jade Goody. I suffered a false positive 36 years ago, and had dire warnings issued about needing to submit to treatment, without any re-testing being offered to check that the result was valid. I should have been dead by now – am not! Another test confirmed what I knew at the time, but was hotly denied, that my results had been mixed up with someone else’s.

    Incidentally, I have just been sent something issuing – allegedly – from Johns Hopkins University that talks in terms of small numbers of cancer cells appearing routinely and being dealt with by the immune system, unless that is otherwise compromised. I think the same sort of thing was discovered many years ago in Vitamin C-related research by Cameron (?).

    The Johns Hopkins piece also talks about the potential damage done by unnecessary treatment, and indeed cancer treatment generally, summarised by someone I know as ‘slash, poison and burn’.

  3. Esther 20 February 2009 at 11:11 pm #

    Thanks Dr B., excellent point. The ‘facts’ obviously need updating to provide accurate and truthful information ” especially about the risk factors ” to allow women to make a more educated decision whether or not a mammogram would be useful to them.

    Another point to consider, as Dr. John Lee (M.D.) says: “The test procedure is unpleasant and the radiation is potentially harmful. Both tissue damage and radiation are known risk factors for breast cancer, so it may even be logical to assume that mammography can CONTRIBUTE to breast cancer.”

    I feel women would be much better off by examining their breast themselves, to avoid common risk factors such as antiperspirants and chemicals in personal care products, and eating a diet rich in organic fruit and vegetables, as well as cutting down on dairy and refined carbohydrates.

    Lee, J., Zava, D. and Hopkins, V. (2002)
    ‘What Your Doctor May Not Tell You About Breast Cancer’
    Warner Books

  4. Anna 21 February 2009 at 1:49 am #

    Thanks for bringing this up; it’s a subject that has been on my mind for several years. I had a benign lump removed when I was in my twenties (back when I consumed more sugar and vegetable oil, too), so I’ve been very vigilant about breast cancer detection issues. I’ve always had dense breasts (common to younger women), which mammography doesn’t image well. I sometimes get lumpy areas that come and go in the various stages of my hormones cycles, especially now that I’m in mid-late 40s (perimenopausal). The last two mammographies were very painful, too. It’s my understanding that it’s been known since the 1920s that some breast cancer cells are very delicate, and spread when handled roughly – yet mammographies require significant pressure and squeezing. What’s up with that? Could mammographies actually contribute to some types of cancers spreading?

    So I looked into thermography, which makes an image of heat radiation from the body. No contact with the imaging machine required, no squeezing. Thermal images can detect areas of increased vascularization (cancer cells create neovascularization to spport their growth) and inflammation (FYI, thermography can also image other parts of the body to find pain and inflammation, which is helpful for “referred pain” that is felt in one area but is generated in another).

    Granted, one of the criticisms of thermography is that it can detect “potential” areas for cancer growth before there is enough cancer to even treat (with current surgical protocol and anti-cancer treatments). There are some who theorize thermography can detect potential cancer sites when merely changing lifestyle or diet could reverse the development (lowwere stress, lower sugar, lowwer intake of inflammatory foods, like high omega-6 vegetable oils).

    Is such early stage detection, that might not even require medical intervention, any reason to instead use technology that detects cancers at more advanced stages and causes discomfort and repeated exposure to radiation? Isn’t “prevention” and “early detection” the better game plan? Or is promotion of mammography technology by big manufacturers like GE part of the equation?

    I don’t know the answers to these questions, but they keep running through my mind every year when I get the postcard from my insurance company reminding me to schedule my mammogram. This year I skipped it and opted for thermography instead (it’s recommended a repeat image is taken again in three months when first establishing a thermography baseline image). I’ll probably do the same next year. Maybe I’ll do a mammography every 5 years, with thermography in between. But I will keep asking questions and learning more. It’s veyr clear to me the picture on mammography is murky, at best.

  5. PJ 21 February 2009 at 6:09 am #

    I remain skeptical about any radiation-based technology being used to ‘detect’ cancer. I suspect if you get enough mammograms you may GET cancer. Not to mention the mauling of the breast that goes on which wouldn’t be good for it either.

    But you know, nobody is ever going to research this, because all the money is in the corporations with the mammogram machines and the various “treatment options” for positive results found with it. This research mostly on ‘false positives’ is probably the best we can hope for, especially since there’s no way to use human trials to see if multiple mammograms eventually over many people have a detrimental health effect.

    I personally think breasts (and prostrate) get cancer mostly because lymph nodes get clogged and eventually the clog (being biochemical and toxic in nature) starts to rot and turn cancerous. This is possible to avoid I suspect, by avoiding chronic- internal allergen-foods (such as wheat and soft dairy), drinking plenty of water (not chemical soda), and gently massaging the lymph system regularly to help it flush out and move through toxins. You know when it’s getting sluggish in there because it’ll hurt like a bruise when you press on the major lymph areas. The worse it hurts the more you need to massage it and drink water.

    The majority of my family in every generation has died from cancer. I attribute my lack of it so far (43) to being aware of these factors. Eating less processed carbs and wheat and sufficient protein and fat has certainly improved my health too though (of course).


  6. Egidija 21 February 2009 at 3:42 pm #

    There are some blood tests that can detest markers for breast cancer. Does anybody know about this form of testing? How accurat can it be , is it possible to do this test in UK and if yes, where?

  7. Margo 23 February 2009 at 6:21 pm #

    I have never had a mammaogram, and never dare to mention it either at work or amongst friends, as I am immediately pinned down, cross-questioned, pitied, looked askance-at, and almost treated as doomed. However, I am the only one who has ever read anything like the above; when I tell others about it they just disbelieve it in preference to the hand-outs.

  8. Esther 24 February 2009 at 1:43 pm #

    PJ, I’m glad to hear you are so healthy against all the genetic odds. And I think you’re right ” the power is where the money is! I trust you know to avoid personal care products containing petrochemicals, parabens etc? For a list of toxic ingredients visit http://lemons.mionegroup.com (under ‘ingredients’ tab).

    Actually, genes can be influenced ” mind over matter really does work! The best example of this is the placebo effect. David Hamilton (PhD), a scientist who worked in the pharmaceutical industry and left to pursue a different approach, has written several books about this, with scientific proof to back it up. I’m a firm believer of this myself ” I’ve had psoriasis for 20 years now and I’ve decided that this year it will go away. I shall have my proof later this year.

    Hamilton, D.
    ‘How Your Mind Can Heal Your Body’ (2008)
    ‘It’s The Thought That Counts’ (2005)

  9. Shirley Bright 26 February 2009 at 9:01 pm #

    I am heartened by the number of comments on this which support my own views on screening. In a group of twelve women with whom I used to work five of them have had breast cancer. I am fairly sure that they all had regular mammograms, but only one case was identified by this, the other four found a lump themselves. However, four other women in the group have experienced “false positives” and spent several weeks in states of intense anxiety as a consequence. I know of similar instances relating to cervical cancer screening. Many years ago I was part of a geographical group (Canterbury) where it was revealed that mistakes were made over a period of several years in the slide examination of cervical smears, and was informed some three years after the screening that mine was to be routinely re-examined. The anxiety this caused was so great that I decided that I would never allow myself to be subjected to this in the future.

    I have asked them to stop badgering me about attending for screening, and told them that I do not wish to use the “service”, but I have had what can only be described as bordering on “threatening letters” from my local health trust trying to scare me into attending for screening. As soon as I receive such a letter now I shred it, immediately, un-read.

  10. helen 2 March 2009 at 1:25 am #

    it seems that the best predictor of cancer is how afraid of it you are. constant testing for something will eventually reap the rewards of seeing what you are testing for, it is as simple as mind over matter! i have to agree with the few here who have never had nor never intend to have screenings. it never ceases to amaze me how people spend their lives in fear just because someone who went to medical school says they should. could the whole we make a fortune off you fearful people be the real reason? the cancer industry is a multi billion dollar concern. lets see who are the real winners here??

  11. Joy 12 March 2009 at 8:23 pm #

    I’m due to be summoned any day now to have another mammogram – but I won’t be going. The older I get the more reactionary I become. I’ve put myself on a high meat and high fat diet and am trying to wean myself off anything in excess of 70gm per day carbohydrates and sugars because the so-called ‘healthy’ diet was really not working for me. I’ve stopped using fluoridated toothpaste and even filter my water so that the artificial fluoride in it is removed (Reverse Osmosis). I am not on any medication and will run a mile if any GP dares to prescribe statins in order to reduce my high cholesterol level – a level which I am carefully and lovingly nurturing since cholesterol is vital for continued efficient brain function.

    Look out everyone – BIG PHARM is out there trying to catch you in a weak moment so that you consume more artificial, unnecessary medicines to swell the coffers for their share-holders.

  12. Kay 17 March 2009 at 6:59 am #

    I recently had my first mammogram after a year of putting it off. I told myself “baseline” for the future. The reason I found this blog is because I’m looking for information on how to cope with the procedure afterward. I believe the technician was as professional as she could be, but the fact I feel so personally violated with the manipulation and the procedure itself is indescribable. Other women (friends) don’t talk about this until you call them reduced to sobs, and even then they have no words to offer except “time will help it pass.” I’d like to see some after-affect research on the indignation women may feel with this procedure. I have a counseling appointment in the morning so I don’t have to miss anymore work due to uncontrolled outbursts of crying, followed by putting on another layer of clothing. I’ve also read a lot today about the thermography technique and will definitely counter any further talk of screenings with this technology. I’m joining the ranks of those not getting another mammogram.

  13. Sammy 4 May 2009 at 8:47 am #

    after being hounded by my doc to get a mammo-i gave in.this being my 2nd ever at age 49.i was feeling fine until then-they found suspicious-clusters-so they did a 2nd –even more intense.i felt toxic in that area for days-and said Id never do it again.it warrented a needle biopsy-saying i have a 1 in 4 chance its cancer.i declined as i dont trust them.i started reading-and couldnt believe the controversy–now its7 months later and ive been feeling sickly in that area-i think they may have done damage and im angry–now not knowing what to do.dr orderes another mammo-i refused.the dr says thermography is a step backwards-and i dont know who to believe-i wish i could find someone with the experience-

  14. Daisy 19 March 2010 at 7:02 pm #

    At my last mammogram, I was told I had microcalcifications and would have to have a mammo every 6 months. When I suggested this was probably more dangerous than just leaving it, they assured me that it was essential to keep an eye on it, as apparently there’s a 50% risk of developing cancer.
    feeling very confused and anxious – has anyone been in the same situation?

  15. Elizabeth 5 September 2010 at 4:15 pm #

    The approach with cancer screening for women has always been the same – inflate the benefits and the risk of the cancer and conceal the harms of testing oh, and totally ignore the legal requirement of informed consent.
    While you’re at it, take a look at cervical screening – a rare cancer and an unreliable test, a bad combination. This test produces so many false positives it should be unethical to even offer it to women or at the very least have some respect for informed consent.
    In Australia we over-screen women against long standing evidence of harm for no additional benefit – we defiantly stick to 2 yearly screening from 18 and claim the program a success if there is any fall in the death rate. No one seems to care about the 77% of Aussie women referred for colposcopy and usually some sort of biopsy during their lifetime (almost all are false positives) – some of these women are left with problems – infertility, miscarriages, problems during pregnancy (requiring a cervical cerclage and the risk of infection), more c-sections, premature babies and psych issues.

    Evidence from the UK and Finland shows that screening women under 25 has no effect on the tiny death rate, but causes huge and harmful over-treatment. How many of you had an abnormal pap in your teens or 20’s? If possible, get the pathology and you’ll find it was a false positive and unnecessary treatment. Cancer in this age group is very rare.
    Two yearly screening of any woman increases the risk of false positives and referral for no additional benefit.
    Finland has the lowest rates of cervical cancer in the world and sends the fewest women for colposcopy and biopsies (fewer false positives) they offer women 5 to 7 tests from age 30. Even this program sends 30% to 55% of women for biopsies, almost all referrals are false positives. Still that’s better than 77% with the Aussie program and 95% for American women.

    You can get a false positive for infections, inflammation, hormonal changes (pregnancy, menopause), trauma (childbirth) and for perfectly normal changes that occur in women in the teens and 20’s. Our immune system takes care of most of these things. If you get an abnormal pap, the chance it’s cancer or a real problem is less than 1% and no more than 1%.

    When only 1% would get this cancer with no screening, it’s shocking to send huge numbers of women for colposcopy and biopsies and with no informed consent.
    Men got risk information quickly for screening for a common cancer, prostate cancer and their informed consent matters, yet women are denied these things for a rare cancer.
    This cancer was in decline before screening started – we know other factors are at work and screening only accounts for some of the cases – more women have had hysterectomies these days, better condoms, fewer women smoke and other unknown factors are at work.
    There are more women looking for answers and fortunately more risk information is coming to light….Dr Angela Raffle tells us, the UK screening expert, that 1000 women need regular tests for 35 years to save ONE woman from cc”….
    American women are the most over-screened and over-treated in the world along with German women. (most women have annual testing from teens)
    Your doctors also promote annual gyn exams that are not backed by evidence and are more likely to harm you – asymptomatic women don’t need routine gyn exams ever. Your doctors also coerce women to screen and have gyn exams in exchange for birth control pills – this is unethical and a violation of your rights, BC has nothing to do with cancer screening.

    Now remember in an unscreened developed country the top risk from this cancer is about 1% (the highest risk I’ve seen is 1.58%, but usually 1% is quoted) – a low risk woman has a risk less than 1%.
    Women in lifetime mutually monogamous relationships have a near zero risk of this cancer. (same with virgins and women who’ve had complete hysterectomies for non-cancerous conditions)
    It’s estimated that 0.65% of women benefit from testing and 0.35% get false negatives and may be disadvantaged by testing. (Richard DeMay article, American pathologist)
    Yet women receive no risk information and there is no informed consent – our Government even pays doctors to reach screening targets for pap smears. This puts our doctors in a potential conflict of interest and clashes with the need to obtain our informed consent. Did your Dr or Papscreen mention these payments to you?
    In the States many doctors are on performance contracts and pap smears would be included.
    The Nordic Cochrane Institute have released their own brochure on mammograms, “The risks and benefits of mammograms” is at their website. NCI were very concerned at the lack of risk information being released to women and women being misled as to the benefits of screening.
    References mentioned here can be found at Dr Joel Sherman’s medical privacy blog under women’s privacy issues – in the side bar are all the references and more.
    I have made an informed decision not to have cervical or breast cancer screening.
    I’m concerned about breast cancer, it is common, but breast exams, self exams and mammograms don’t work or expose me to risk….I’ve therefore adopted a method called breast awareness – just taking note of the look and shape of your breasts in the mirror each morning after showering. This method was devised by the late Dr Joan Austoker from Oxford University.

    Whether you have screening or not is not that important, as long as it’s an informed decision – your health may depend on it.

  16. Elizabeth 5 September 2010 at 4:18 pm #

    Sammy, screening under 50 is very controversial, most countries recommend screening 2-3 yearly from age 50.
    Take a look at the Nordic Cochrane reference – you’ll find it at Dr Sherman’s site and at the Violet to Blue site.

  17. Elizabeth 5 September 2010 at 4:21 pm #

    I should add the UK cervical screening program sends 65% of women for colposcopy/biopsies and your doctors also receive financial incentives to reach screening targets.

  18. Elizabeth 5 September 2010 at 4:32 pm #

    Sorry, but just remembered some of you might like to contribute to the discussion at “blogcritics and unnecessary pap smears” – many women who’ve been harmed by testing & lots of great references. (many from the UK) More than 1500 posts so far…
    You lucky to have some great advocates for women’s rights and informed consent in the UK – Dr Raffle, Prof Baum, Margaret McCartney and others.

  19. mrs rita barnes 28 January 2011 at 2:40 am #

    iam left very anxious and worried after my recent 2yrly check i could do without this stress as i am only just getting over my 44yr old daughters untimely death last yr was an open verdict and my nephew 18mth before same age i am 63 and facing the dreaded recal even though i have always been all clear as routine two stage,imay be asked to have aultrasound i had hysterectomy in 1985 for other reason than any disease just hope it will be a false pos/i felt alright til i got the letter

  20. Elizabeth (Aust) 4 February 2011 at 11:21 am #

    If I’ve got it right, you’ve had an abnormal pap smear 26 years after you had a hysterectomy for benign reasons (not cancer).
    Did the hysterectomy include your cervix? If so, you’re testing unnecessarily. Women who’ve had complete hysterectomies for non-cancerous conditions don’t benefit from pap tests and the test is not recommended for you.
    Otherwise, some countries stop testing at age 60 – you might want to assess your risk profile and decide whether you want to have more testing.
    As a low risk woman, I have always declined pap tests. The worry from call backs is awful and bad for your health – studies have shown the negative psychological impact stays with women for some time after they get the all clear.
    Remember this cancer is rare and the test unreliable and produces lots of false positives.
    Lifetime risk of cancer is less/no more than 1% (0.65% in Australia and 1% in America – at most) but false positives affect most women at some stage due to over-screening and inappropriate screening – 95% will be referred in the States, 77% in Australia.
    Try to remember the risk is very small and tiny if you’re low risk and if you have no cervix – well, you’re more likely to be beamed up by aliens than get cervical cancer.
    Hope everything works out for you.

  21. Deborah 4 July 2011 at 3:34 am #

    Women considering mammograms – stop and go to the Medphyzz site and listen to the 35 minute lecture by Prof Michael Baum, UK breast cancer surgeon, “Breast cancer screening: the inconvenient truths”.
    It may save you from a lot of grief.
    I don’t have pap tests or mammograms. I agree these decisions should be made my individual women after assessing their risk profile and the cos and pluses of testing, but that’s impossible given the poor information we receive from the profession and the screening authorities.
    Screening is a gamble and should not be sold to us with puff, spin and using scare campaigns. I want the facts, there is too much at stake. Government screening targets and target payments to doctors should be axed. If only 25% of women make an informed decision to screen, so be it…we don’t force others into the program using unethical tactics just to satisfy targets and make profits.
    Ever noticed these measures are not used against men? No target payments and men get full information, at least that’s the case in Australia.

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